2b5a | pdb_00002b5a
C.BclI, Control Element of the BclI Restriction-Modification System
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Overview
Protection from DNA invasion is afforded by restriction-modification, systems in many bacteria. The efficiency of protection depends crucially, on the relative expression levels of restriction versus methytransferase, genes. This regulation is provided by a controller protein, named C, protein. Studies of the Bcll system in E. coli suggest that C.Bcll, functions as a negative regulator for M.Bcll expression, implying that it, plays a role in defense against foreign DNA during virus infection. C.Bcll, binds (Kd = 14.3 nM) to a 2-fold symmetric C box DNA sequence that, overlaps with the putative -35 promoter region upstream of the bcllM and, bcllC genes. The C.Bcll fold comprises five alpha helices: two helices, form a helix-turn-helix motif, and the remaining three helices form the, extensive dimer interface. The C.Bcll-DNA model proposed suggests that DNA, bending might play an important role in gene regulation, and that Glu27, and Asp31 in C.Bcll might function critically in the regulation.
About this Structure
2B5A is a Protein complex structure of sequences from Bacillus caldolyticus with ACY as ligand. Full crystallographic information is available from OCA.
Reference
Crystal structure of the restriction-modification system control element C.Bcll and mapping of its binding site., Sawaya MR, Zhu Z, Mersha F, Chan SH, Dabur R, Xu SY, Balendiran GK, Structure. 2005 Dec;13(12):1837-47. PMID:16338412
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