1vfj: Difference between revisions

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

The Thermus thermophilus HB8 genome encodes a signal transducing PII protein, GlnK. The crystal structures of GlnK have been determined in two different space groups, P2(1)2(1)2(1) and P3(1)21. The PII protein has the T-loop, which is essential for interactions with receptor proteins. In both crystal forms, three GlnK molecules form a trimer in the asymmetric unit. In one P2(1)2(1)2(1) crystal form, the three T-loops in the trimer are disordered, while in another P2(1)2(1)2(1) crystal form, the T-loop from one molecule in the trimer is ordered. In the P3(1)21 crystal, one T-loop is ordered while the other two T-loops are disordered. The conformations of the ordered T-loops significantly differ between the two crystal forms; one makes the alpha-helix in the middle of the T-loop, while the other has an extension of the beta-hairpin. Two different conformations are captured by the crystal contacts. The observation of multiple T-loop conformations suggests that the T-loop could potentially exhibit "polysterism," which would be important for interactions with receptor proteins. The crystal structures of the nucleotide-bound forms, GlnK.ATP and GlnK.ADP, have also been determined. ATP/ADP binding within a cleft at the interface of two adjacent T. thermophilus GlnK monomers might affect the conformation of the T-loop.

1VFJ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermus_thermophilus Thermus thermophilus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1VFJ OCA].  

[[Category: RSGI, RIKEN Structural Genomics/Proteomics Initiative.]]

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