tag:blogger.com,1999:blog-84434712605052565882024-03-21T03:14:37.756-07:00NitrogenaseGot nitrogen? It can fix that.Gill.http://www.blogger.com/profile/01015808121561564016noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-8443471260505256588.post-5743326818643936812011-04-30T10:14:00.001-07:002011-04-30T10:14:55.313-07:00Vote Nitrogenase!<div class="WordSection1"><div class="MsoNormal"><div class="separator" style="clear: both; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; text-align: center;"><span class="Apple-style-span" style="margin-left: 1em; margin-right: 1em;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtTl3orvitKrsN1axgy3SERPUOhtTFY6XeJ23IYO8rh2gLXdEmx3GlTRlharznqDyijgrq0Pqvht7EKN-nerXE7M3ahjQJF4XlfIgf80DPMZFrvhi11J22KjcK15Fsu9zsx0PC-n_QOMQ/s1600/Fe-S+centers.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtTl3orvitKrsN1axgy3SERPUOhtTFY6XeJ23IYO8rh2gLXdEmx3GlTRlharznqDyijgrq0Pqvht7EKN-nerXE7M3ahjQJF4XlfIgf80DPMZFrvhi11J22KjcK15Fsu9zsx0PC-n_QOMQ/s400/Fe-S+centers.png" style="cursor: move;" width="400" /></a></span></div><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><br />
</div><div align="center" class="MsoCaption" style="text-align: center;"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><span class="Apple-style-span" style="font-family: Times, 'Times New Roman', serif;">Figure 1: Nitrogenase. PDB: 1M</span><span class="Apple-style-span" style="font-family: Times, 'Times New Roman', serif;">1N</span></div></div><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><br />
</div><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><span style="font-family: 'Century Gothic', sans-serif; font-size: 13pt;">N</span><span style="font-family: 'Century Gothic', sans-serif; font-size: 13pt;">itrogenase, an enzyme produced by bacteria in</span><span class="Apple-style-span" style="font-family: 'Century Gothic', sans-serif; font-size: 17px;"> the root nodules of many legumes, performs the important nitrogen fixation reaction:</span></div></div><div class="MsoNormal"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><br />
</div></div><div align="center" class="MsoNormal" style="text-align: center;"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><b><span style="font-family: 'Century Gothic', sans-serif; font-size: 22pt;">N≡N → 2 NH<sub>3</sub></span></b><b><sub><span style="font-family: 'Century Gothic', sans-serif; font-size: 8pt;"><o:p></o:p></span></sub></b></div></div><div align="center" class="MsoNormal" style="text-align: center;"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><span style="font-family: 'Century Gothic', sans-serif; font-size: 10pt;">(not balanced)<o:p></o:p></span></div></div><div class="MsoNormal"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><br />
</div></div><div class="MsoNormal"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><i><span style="font-family: 'Century Gothic', sans-serif; font-size: 17pt;">But why does it deserve your vote?<o:p></o:p></span></i></div></div><div class="MsoNormal"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><br />
</div></div><div class="MsoNormal"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><b><span style="font-family: 'Century Gothic', sans-serif; font-size: 13pt;">1</span></b><span style="font-family: 'Century Gothic', sans-serif; font-size: 13pt;">. <b><i>This transformation is incredible</i></b>. Consider this: the N<u>=</u>N bond is 945 kJ/mol strong. This makes nitrogen gas incredibly difficult to reduce. But nitrogenase does it. It has also been shown to split other molecules <i>in vitro, </i>such as carbon dioxide and ethene.<o:p></o:p></span></div></div><div class="MsoNormal"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><br />
</div></div><div class="MsoNormal"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><b><span style="font-family: 'Century Gothic', sans-serif; font-size: 13pt;">2</span></b><span style="font-family: 'Century Gothic', sans-serif; font-size: 13pt;">. <b><i>Nitrogenase does it better than Haber-Bosch.</i> </b>If you recall the Haber-Bosch process, you may remember that to perform the same reaction shown above, an iron catalyst, calcium, potassium, and aluminum oxides, temperatures between 300 and 500˚C, and pressures of 15-20 MPa are required. Nitrogenase performs the same reaction under biological temperatures and pressures with 8 electrons, 8 protons and 16 ATP per transformation. Looks like this enzyme has got us beat.<o:p></o:p></span></div></div><div class="MsoNormal"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><br />
</div></div><div class="MsoNormal"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><b><span style="font-family: 'Century Gothic', sans-serif; font-size: 13pt;">3</span></b><span style="font-family: 'Century Gothic', sans-serif; font-size: 13pt;">. <b><i>Sweet cofactors</i>.</b> Fe-S clusters? Right on. Molybdenum-Fe-S clusters? Even better. What exactly does the molybdenum do? Scientists have yet to provide a definitive answer to that question. <o:p></o:p></span></div></div><div class="MsoNormal"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><br />
</div></div><div class="separator" style="clear: both; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1D13xqGkYluuXzmTTxgoQwzalYIEE_TtumDe5kfKcE1ebr-24ZPvyTJZmkBMlgXKdCO0h1NA8QMTl1OXzYBx6lr6y_v0xzkgo0bEQ4Gxiat8uRHhaEA5IuU-ZC2tuwUPR34R8u0jAz34/s1600/Molybdenum+Center.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span class="Apple-style-span" style="color: black;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1D13xqGkYluuXzmTTxgoQwzalYIEE_TtumDe5kfKcE1ebr-24ZPvyTJZmkBMlgXKdCO0h1NA8QMTl1OXzYBx6lr6y_v0xzkgo0bEQ4Gxiat8uRHhaEA5IuU-ZC2tuwUPR34R8u0jAz34/s320/Molybdenum+Center.png" style="cursor: move;" width="320" /></span></a></div><div class="MsoCaption" style="text-align: center;"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;">Figure 2: Molybdenum-Iron-Sulfur Cluster in Nitrogenase protein. PDB: 1MIO.<span style="font-family: 'Century Gothic', sans-serif; font-size: 14pt;"><o:p></o:p></span></div></div><div class="MsoNormal"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><br />
</div></div><div class="MsoNormal"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><b><span style="font-family: 'Century Gothic', sans-serif; font-size: 13pt;">4</span></b><span style="font-family: 'Century Gothic', sans-serif; font-size: 14pt;">. <b><i><u>6 bonds to Carbon</u></i>!</b></span><b><span style="font-family: 'Century Gothic', sans-serif; font-size: 13pt;"> </span></b><span style="font-family: 'Century Gothic', sans-serif; font-size: 13pt;">To the horror of organic chemists, nitrogenase's ability to split a variety of organic molecules other than nitrogen gas implicates the existence of a six-coordinate atom within the Mo-Fe-S cluster. The reality of this coordination has not been officially confirmed by bioinorganic chemists, but remains an accepted conclusion in many circles<a href="http://www.blogger.com/post-edit.g?blogID=2981092797075976874&postID=2996266247152023993#_edn1" name="_ednref1" title=""><span class="MsoEndnoteReference"><span class="MsoEndnoteReference"><span style="font-family: 'Century Gothic', sans-serif; font-size: 13pt;">[1]</span></span></span></a>.<o:p></o:p></span></div></div><div class="separator" style="clear: both; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjiNR7rJPWgQalgBi3a3jk2GBzLg0WF_2oY4dLxfsfkGoyowBDVDvzYbO24PCn-JJCttK6DBTD18o8goPDZB2_q9Mdicw0WhCcnctFVwI2hpY9FqAHbcCmKFwsdH3i3QFT4x4vb5YphSlM/s1600/carbon.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span class="Apple-style-span" style="color: black;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjiNR7rJPWgQalgBi3a3jk2GBzLg0WF_2oY4dLxfsfkGoyowBDVDvzYbO24PCn-JJCttK6DBTD18o8goPDZB2_q9Mdicw0WhCcnctFVwI2hpY9FqAHbcCmKFwsdH3i3QFT4x4vb5YphSlM/s320/carbon.jpg" style="cursor: move;" width="193" /></span></a></div><div align="center" class="MsoNormal" style="text-align: center;"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;">Figure 3: Schematic drawing of six-coordinate center. Speculation suggests that a carbon atom could exist in this coordination, but the majority of published articles assume it to be a nitrogen atom<a href="http://www.blogger.com/post-edit.g?blogID=2981092797075976874&postID=2996266247152023993#_edn2" name="_ednref2" title=""><span class="MsoEndnoteReference"><span class="MsoEndnoteReference"><b><span style="font-family: 'Times New Roman', serif;">[2]</span></b></span></span></a>.</div></div></div><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><span style="font-family: 'Century Gothic', sans-serif; font-size: 14pt;"><br clear="all" style="page-break-before: auto;" /></span></div><div class="WordSection2"><div class="MsoNormal"><div style="text-align: center;"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><span style="font-family: 'Century Gothic', sans-serif;"><o:p><span class="Apple-style-span" style="font-size: medium;"> </span><i><span class="Apple-style-span" style="font-size: x-large;">Vote Nitrogenase!</span></i></o:p></span></div></div><div style="text-align: center;"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><span style="font-family: 'Century Gothic', sans-serif;"><o:p><i><span class="Apple-style-span" style="font-size: x-large;"><br />
</span></i></o:p></span></div></div></div></div><div><hr align="left" size="1" width="33%" /><div id="edn1"><div class="MsoEndnoteText"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><span class="Apple-style-span" style="color: black;"><a href="http://www.blogger.com/post-edit.g?blogID=2981092797075976874&postID=2996266247152023993#_ednref1" name="_edn1" title=""><span class="MsoEndnoteReference"><span class="MsoEndnoteReference"><span style="font-family: 'Times New Roman', serif; font-size: 10pt;">[1]</span></span></span></a> For more information, feel free to chat with Professor David Benson of the Calvin College Chemistry and Biochemistry Department.</span></div></div></div><div id="edn2"><div class="MsoEndnoteText"><div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;"><span class="Apple-style-span" style="color: black;"><a href="http://www.blogger.com/post-edit.g?blogID=2981092797075976874&postID=2996266247152023993#_ednref2" name="_edn2" title=""><span class="MsoEndnoteReference"><span class="MsoEndnoteReference"><span style="font-family: 'Times New Roman', serif; font-size: 10pt;">[2]</span></span></span></a> <span class="apple-style-span">Einsle, O., Tezcan, F., Andrade, S., Schmid, B., Yoshida, M., Howard, J., Rees, D. Nitrogenase MoFe-Protein at 1.16 Å Resolution: A Central Ligand in the Fe-Mo cofactor.</span><span class="apple-converted-space"> </span><span class="apple-style-span"><i>Science</i></span><span class="apple-converted-space"> </span><span class="apple-style-span">297, 1696-1699.</span></span></div></div></div></div>Gill.http://www.blogger.com/profile/01015808121561564016noreply@blogger.com4tag:blogger.com,1999:blog-8443471260505256588.post-43072677029103647092011-03-18T07:24:00.000-07:002011-03-18T07:27:01.870-07:00Nitrogenase: Not Just Another "Bosch-up"<div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;"></div><div class="MsoNormal" style="font-family: Times, serif; line-height: normal; margin-bottom: 0.0001pt;"><span style="color: black; font-family: Times, serif; font-size: x-small;">A</span><span style="color: black; font-family: Times, serif;">tmospheric nitrogen is extremely stable. Even the traditional Lewis representation of the homodiatomic molecule, :N<u>=</u>N:, gives some indication of the enormous amounts of energy required to break this triple bond. Industrially the degradation of nitrogen was accomplished through the Haber-Bosch process, which employs the use of an iron catalyst along with calcium, potassium, and aluminum oxides, temperatures from between 300-500˚C, and pressures of 15-20 MPa. The Haber-Bosch process was hailed for its use in fertilizer production, as many believe the current human population could not have been sustained without it, but its harsh conditions and its potential use in explosives manufacturing cause some to view this reaction with disdain.</span></div><div align="center" class="MsoNormal" style="font-family: Times, serif; line-height: normal; margin-bottom: 0.0001pt; text-align: center;"><span style="color: black; font-family: Times, serif;">N<sub>2</sub> + 3 H<sub>2</sub> </span><span style="color: black; font-family: 'Cambria Math', serif;">⇌</span><span style="color: black; font-family: Times, serif;"> 2 NH<sub>3</sub></span></div><div class="MsoNormal" style="font-family: Times, serif; line-height: normal; margin-bottom: 0.0001pt;"><span style="color: black; font-family: Times, serif;">The biological fixation of nitrogen in to ammonia, however, should not be viewed with distaste as the Haber-Bosch process perhaps warrants. For millions of years bacterial species have fixed the extremely stable atmospheric nitrogen - the results being nothing but beneficial. The process is energetically taxing, but is efficiently accomplished by the work of an enzyme known as <b>Nitrogenase. </b></span><span style="color: black; font-family: 'Times New Roman', serif;"><o:p></o:p></span></div><div class="MsoNormal" style="font-family: Times, serif; line-height: normal; margin-bottom: 0.0001pt;"><br />
</div><div class="MsoNormal" style="font-family: Times, serif; line-height: normal; margin-bottom: 0.0001pt;"><span style="color: black; font-family: Times, serif;">Nitrogenase isolated from <i>Azotobacter vinelandii</i> was shown to be a dimer, with one subunit containing a Fe cofactor and the other containing a Mo-Fe cofactor. The Fe subunit functions to provide a constant electron flow from ATP breakdown in order to fuel the Mo-Fe subunit's scission of the :N<u>=</u>N: bond<a href="file:///C:/Users/Dell/Documents/Spring%202011/Biochem/Protein%20Assignment/Assignment%202.docx#_ftn1" name="_ftnref1" title=""><span class="MsoFootnoteReference"><span class="MsoFootnoteReference"><span style="color: black; font-family: Times, serif; line-height: 115%;">[1]</span></span></span></a>. These two subunits are shown to covalently cross-link between a glutamine residue on the Fe subunit and a lysine residue on the MoFe subunit during the catalytic mechanism<a href="file:///C:/Users/Dell/Documents/Spring%202011/Biochem/Protein%20Assignment/Assignment%202.docx#_ftn2" name="_ftnref2" title=""><span class="MsoFootnoteReference"><span class="MsoFootnoteReference"><span style="color: black; font-family: Times, serif; line-height: 115%;">[2]</span></span></span></a>. Other mechanistic studies have isolated a hexa-coordinated ligand within the Fe-Mo complex, which is argued to be a single nitrogen atom<a href="file:///C:/Users/Dell/Documents/Spring%202011/Biochem/Protein%20Assignment/Assignment%202.docx#_ftn3" name="_ftnref3" title=""><span class="MsoFootnoteReference"><span class="MsoFootnoteReference"><span style="color: black; font-family: Times, serif; line-height: 115%;">[3]</span></span></span></a>. The implication is that the enzymatic stabilization of the lone nitrogen atom greatly contributes to the efficacy of the nitrogenase mechanism.<o:p></o:p></span></div><div style="font-family: Times, serif; line-height: 13.5pt; margin-bottom: 0.0001pt; margin-left: 0in; margin-right: 0in; margin-top: 0in;"><br />
</div><div style="font-family: Times, serif;"><hr align="left" size="1" style="font-size: large;" width="33%" /><div id="ftn1"><div class="MsoNormal" style="line-height: 13.5pt; margin-bottom: 4.5pt; margin-left: 0in; margin-right: 0in; margin-top: 4.5pt;"><span class="Apple-style-span" style="font-size: x-small;"><a href="file:///C:/Users/Dell/Documents/Spring%202011/Biochem/Protein%20Assignment/Assignment%202.docx#_ftnref1" name="_ftn1" title=""><span class="MsoFootnoteReference"><span class="MsoFootnoteReference"><span style="font-family: Calibri, sans-serif; line-height: 115%;">[</span><span style="font-family: Calibri, sans-serif; line-height: 115%;">1]</span></span></span></a> <span style="color: #222222; font-family: 'Times New Roman', serif;">Schindelin, H., Kisker, C., Schlessman, J., Howard, J., and Rees, D. (1997) </span><span style="color: black; font-family: 'Times New Roman', serif;">Structure of ADP x AIF4(-)-stabilized nitrogenase complex and its implications for signal transduction. <i>Nature</i> 387, 370-376.</span><b><span style="color: #222222; font-family: 'Times New Roman', serif;"><o:p></o:p></span></b></span></div></div><div id="ftn2"><div style="line-height: 13.5pt; margin-bottom: 7.5pt; margin-left: 0in; margin-right: 0in; margin-top: 3.75pt;"><span class="Apple-style-span" style="font-size: x-small;"><a href="file:///C:/Users/Dell/Documents/Spring%202011/Biochem/Protein%20Assignment/Assignment%202.docx#_ftnref2" name="_ftn2" title=""><span class="MsoFootnoteReference"><span class="MsoFootnoteReference"><span style="font-family: 'Times New Roman', serif; line-height: 115%;">[2]</span></span></span></a> <span style="color: #222222;">Schmid, B., Einsle, O., Chiu, H., Willing, A., Yoshida, M., Howard, J., Rees, D. (2002)<i> Biochemistry</i> 41,15557-15565.<o:p></o:p></span></span></div></div><div id="ftn3"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span class="Apple-style-span" style="font-size: x-small;"><a href="file:///C:/Users/Dell/Documents/Spring%202011/Biochem/Protein%20Assignment/Assignment%202.docx#_ftnref3" name="_ftn3" title=""><span class="MsoFootnoteReference"><span style="font-family: 'Times New Roman', serif;"><span class="MsoFootnoteReference"><span style="font-family: 'Times New Roman', serif; line-height: 115%;">[3]</span></span></span></span></a><span style="font-family: 'Times New Roman', serif;"> Einsle, O., Tezcan, F., Andrade, S., Schmid, B., Yoshida, M., Howard, J., Rees, D. Nitrogenase MoFe-Protein at 1.16 Å Resolution: A Central Ligand in the Fe-Mo cofactor. <i>Science</i> 297, 1696-1699.</span></span><span style="font-family: Bliss-Heavy; font-size: 6.5pt;"><o:p></o:p></span></div></div></div>Gill.http://www.blogger.com/profile/01015808121561564016noreply@blogger.com1tag:blogger.com,1999:blog-8443471260505256588.post-5274767295345890232011-03-01T19:11:00.000-08:002011-03-01T19:11:27.393-08:00Assignment #1<div class="separator" style="clear: both; text-align: center;"><b><span class="Apple-style-span" style="font-family: Verdana, sans-serif;">Nitrogenase Dimer</span></b></div><div class="separator" style="clear: both; text-align: center;"><span class="Apple-style-span" style="font-family: Verdana, sans-serif;">PDB: 1G5P</span></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhIM3mnSFgCGlhv7M3HBmwwvZch8imbX7WULO1kDM40VU7Mps2Qn1pcKC84WXpdkyrUfm7fg80E45mq20G3NiAFSxpGNs0yNlXGpZyycLwPY9d-Z5xwPKR_laoDqtiGg0aumE7guXmVca4/s1600/1G5P+Nitrogenase+Dimer.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhIM3mnSFgCGlhv7M3HBmwwvZch8imbX7WULO1kDM40VU7Mps2Qn1pcKC84WXpdkyrUfm7fg80E45mq20G3NiAFSxpGNs0yNlXGpZyycLwPY9d-Z5xwPKR_laoDqtiGg0aumE7guXmVca4/s320/1G5P+Nitrogenase+Dimer.png" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><span class="Apple-style-span" style="font-family: Verdana, sans-serif;"><br />
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</span></b></div><div class="separator" style="clear: both; text-align: center;"><b><span class="Apple-style-span" style="font-family: Verdana, sans-serif;">Tetramer</span></b></div><div class="separator" style="clear: both; text-align: center;"><span class="Apple-style-span" style="font-family: Verdana, sans-serif;">PDB: 1MIO</span></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2AX9A7qQVrkQojNmzgAYZwxlOnqH2EoSyf0-ZuTSLEv4ibcp4qkHszn-9Grr1gcfpxgL8r4UPkYv3sQrRP_08f1eR9KP85Ut0Kqh8sY_d1g0OGDxMih3xJUl3QU2Ay16UkngwYZrqH2E/s1600/Nitrogenase+1MIO+quatramer.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="217" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2AX9A7qQVrkQojNmzgAYZwxlOnqH2EoSyf0-ZuTSLEv4ibcp4qkHszn-9Grr1gcfpxgL8r4UPkYv3sQrRP_08f1eR9KP85Ut0Kqh8sY_d1g0OGDxMih3xJUl3QU2Ay16UkngwYZrqH2E/s320/Nitrogenase+1MIO+quatramer.png" width="320" /></a></div><b><br />
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<div style="text-align: center;"><b><span class="Apple-style-span" style="font-family: Verdana, sans-serif;">Fe-S Centers</span></b></div><div style="text-align: center;"><span class="Apple-style-span" style="font-family: Verdana, sans-serif;">PDB: 1M1N</span></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNznZYRKt7q_cGM-aHHhMLjg0GnAmYiRu4ny-N8I8YFfy_y7c05mX1Do0M0d7KSq4p6m3Wbm1co21oFiU2JsIEMBkZAtuDEAdt7a2BJI6cv2rid8lyR-rpJVKITyKXORBV5wn2oEjOpD0/s1600/Fe-S+centers.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNznZYRKt7q_cGM-aHHhMLjg0GnAmYiRu4ny-N8I8YFfy_y7c05mX1Do0M0d7KSq4p6m3Wbm1co21oFiU2JsIEMBkZAtuDEAdt7a2BJI6cv2rid8lyR-rpJVKITyKXORBV5wn2oEjOpD0/s320/Fe-S+centers.png" width="320" /></a></div><div style="text-align: center;"><span class="Apple-style-span" style="font-family: Verdana, sans-serif;"><br />
</span></div><div style="text-align: center;"><b><span class="Apple-style-span" style="font-family: Verdana, sans-serif;">Molybdenum-Fe-S Complex</span></b></div><div style="text-align: center;"><span class="Apple-style-span" style="font-family: Verdana, sans-serif;">PDB: 1MIO</span></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiOXtlog1ZLeb3PfXlfadFtEYjDjk2Okeg-KN6yTTrE9p0Nvuew7yeB8cgaYA29a2DKJ8g4todkj2zsJ8miAIHlLVLMv_uOyHO5AJSw0doWHexUTdhT3IS9mbxc7hTcfk8sxKxrbOmkqNI/s1600/Molybdenum+Center.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiOXtlog1ZLeb3PfXlfadFtEYjDjk2Okeg-KN6yTTrE9p0Nvuew7yeB8cgaYA29a2DKJ8g4todkj2zsJ8miAIHlLVLMv_uOyHO5AJSw0doWHexUTdhT3IS9mbxc7hTcfk8sxKxrbOmkqNI/s320/Molybdenum+Center.png" width="320" /></a></div><div style="text-align: center;"><span class="Apple-style-span" style="font-family: Verdana, sans-serif;"><br />
</span></div><div style="text-align: center;"><span class="Apple-style-span" style="font-family: Verdana, sans-serif;"><b>Mg & ADP Binding</b></span></div><div style="text-align: center;"><span class="Apple-style-span" style="font-family: Verdana, sans-serif;">PDB: 1NIP</span></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLBYURydRlU1B5_BduIYZOOSyOxaouMwlqlf832zIg7tN3JVCwgsRWt4XUWkKYlTfhwWiBUUl8zgMM7eARsSDKvLAxUriyzLraqedeGXGOxGq-NLDd4krmsbjVNkXlTs4VVju5TXJA1LY/s1600/Mg+ADP+cofactors.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="217" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLBYURydRlU1B5_BduIYZOOSyOxaouMwlqlf832zIg7tN3JVCwgsRWt4XUWkKYlTfhwWiBUUl8zgMM7eARsSDKvLAxUriyzLraqedeGXGOxGq-NLDd4krmsbjVNkXlTs4VVju5TXJA1LY/s320/Mg+ADP+cofactors.png" width="320" /></a></div><div style="text-align: center;"><span class="Apple-style-span" style="font-family: Verdana, sans-serif;"><br />
</span></div>Gill.http://www.blogger.com/profile/01015808121561564016noreply@blogger.com1