1mkm

From Proteopedia

Revision as of 22:18, 2 May 2008

Template:STRUCTURE 1mkm

CRYSTAL STRUCTURE OF THE THERMOTOGA MARITIMA ICLR

Overview

Members of the IclR family of transcription regulators modulate signal-dependent expression of genes involved in carbon metabolism in bacteria and archaea. The Thermotoga maritima TM0065 gene codes for a protein (TM-IclR) that is homologous to the IclR family. We have determined the crystal structure of TM-IclR at 2.2 A resolution using MAD phasing and synchrotron radiation. The protein is composed of two domains: the N-terminal DNA-binding domain contains the winged helix-turn-helix motif, and the C-terminal presumed regulatory domain is involved in binding signal molecule. In a proposed signal-binding site, a bound Zn(2+) ion was found. In the crystal, TM-IclR forms a dimer through interactions between DNA-binding domains. In the dimer, the DNA-binding domains are 2-fold related, but the dimer is asymmetric with respect to the orientation of signal-binding domains. Crystal packing analysis showed that TM-IclR dimers form a tetramer through interactions exclusively by signal-binding domains. A model is proposed for binding of IclR-like factors to DNA, and it suggests that signal-dependent transcription regulation is accomplished by affecting an oligomerization state of IclR and therefore its affinity for DNA target.

About this Structure

1MKM is a Single protein structure of sequence from Thermotoga maritima. This structure supersedes the now removed PDB entry 1jmr. Full crystallographic information is available from OCA.

Reference

Crystal structure of Thermotoga maritima 0065, a member of the IclR transcriptional factor family., Zhang RG, Kim Y, Skarina T, Beasley S, Laskowski R, Arrowsmith C, Edwards A, Joachimiak A, Savchenko A, J Biol Chem. 2002 May 24;277(21):19183-90. Epub 2002 Mar 4. PMID:11877432 Page seeded by OCA on Sat May 3 01:18:35 2008