1v3s

From Proteopedia

Revision as of 12:40, 20 March 2008

Crystal structure of TT1020 from Thermus thermophilus HB8

Overview

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.

About this Structure

1V3S is a Single protein structure of sequence from Thermus thermophilus. Full crystallographic information is available from OCA.

Reference

Crystal structures of the signal transducing protein GlnK from Thermus thermophilus HB8., Sakai H, Wang H, Takemoto-Hori C, Kaminishi T, Yamaguchi H, Kamewari Y, Terada T, Kuramitsu S, Shirouzu M, Yokoyama S, J Struct Biol. 2005 Jan;149(1):99-110. PMID:15629661

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