1fca: Difference between revisions

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

Ferredoxins (Fd) are electron-carrier proteins, the active sites of which are organized around clusters made of iron and inorganic sulfur. The Fd from Clostridium acidurici is 55 amino acids long and contains two [4Fe-4S] clusters. Crystals have been obtained in the space group P4(3)2(1)2, a = b = 34.441 (5), c = 74.778 (9) A. The structure was solved by molecular replacement using the Fd from Peptostreptcoccus asaccharolyticus as a search model, these two ferredoxins having 37 residues in common. Refinement using molecular-dynamics techniques was then initiated. Successive rounds of model building and refinement gave a structure that includes 45 water molecules with R = 15%. At this stage, the electron-density map clearly revealed discrepancies in the position of two amino acids in the published primary sequence. Refinement based on these modifications led to R = 14.3% for 3921 reflections up to 1.8 A, resolution. The geometry of the two clusters has been found to be in good agreement with that previously obtained at a lower resolution. Interactions of polypeptide chain with the [4Fe-4S] clusters, the cluster geometry as well as the hydrogen bonds involving S, Sgamma, N and water molecules are reported.

1FCA is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Clostridium_acidurici Clostridium acidurici] with <scene name='pdbligand=SF4:'>SF4</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1FCA OCA].  

[[Category: Jesior, J C.]]

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