1mz4: Difference between revisions

[[Image:1mz4.gif|left|200px]]<br /><applet load="1mz4" size="350" color="white" frame="true" align="right" spinBox="true"  

First, the crystal structure of cytochrome c-550 (the psbV1 gene product) from the thermophilic cyanobacterium Thermosynechococcus elongatus has been determined to a resolution of 1.8 A. A comparison of the T. elongatus cytochrome c-550 structure to its counterparts from mesophilic organisms, Synechocystis 6803 and Arthrospira maxima, suggests that increased numbers of hydrogen bonds may play a role in the structural basis of thermostability. The cytochrome c-550 in T. elongatus also differs from that in Synechocystis 6803 and Arthrospira maxima in its lack of dimerization and the presence of a trigonal planar molecule, possibly bicarbonate, tightly bound to the heme propionate oxygen atoms. Cytochromes c-550 from T. elongatus, Synechocystis 6803 and Arthrospira maxima exhibit different EPR spectra. A correlation has been done between the heme-axial ligands geometries and the rhombicity calculated from the EPR spectra. This correlation indicates that binding of cytochrome c-550 to Photosystem II is accompanied by structural changes in the heme vicinity. Second, the psbV2 gene product has been found and purified. The UV-visible, EPR and Raman spectra are reported. From the spectroscopic data and from a theoretical structural model based on the cytochrome c-550 structure it is proposed that the 6th ligand of the heme-iron is the Tyr86.

1MZ4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermosynechococcus_elongatus Thermosynechococcus elongatus] with <scene name='pdbligand=PO4:'>PO4</scene>, <scene name='pdbligand=BCT:'>BCT</scene>, <scene name='pdbligand=HEM:'>HEM</scene> and <scene name='pdbligand=GOL:'>GOL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MZ4 OCA].  

[[Category: Kerfeld, C A.]]

[[Category: Sawaya, M R.]]

[[Category: Tran, K T.]]

[[Category: Yeates, T O.]]

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