5W5A

Crystal structure of Mycobacterium tuberculosis CRP-FNR family transcription factor Cmr (Rv1675c)

5W5A の概要

• エントリーDOI: 10.2210/pdb5w5a/pdb
• 関連するPDBエントリー: 5W5B
• 分子名称: HTH-type transcriptional regulator Cmr, SULFATE ION, CHLORIDE ION, ... (4 entities in total)
• 機能のキーワード: transcription factor, crp/fnr family, helix-turn-helix, transcription
• 由来する生物種: Mycobacterium tuberculosis H37Rv
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 54997.09

構造登録者

Cheung, J.,Cassidy, M.,Ginter, C.,Ranganathan, S.,Pata, D.J.,McDonough, K.A. (登録日: 2017-06-14, 公開日: 2017-12-13, 最終更新日: 2024-10-23)

主引用文献

Ranganathan, S.,Cheung, J.,Cassidy, M.,Ginter, C.,Pata, J.D.,McDonough, K.A.
Novel structural features drive DNA binding properties of Cmr, a CRP family protein in TB complex mycobacteria.
Nucleic Acids Res., 46:403-420, 2018

PubMed Abstract: Mycobacterium tuberculosis (Mtb) encodes two CRP/FNR family transcription factors (TF) that contribute to virulence, Cmr (Rv1675c) and CRPMt (Rv3676). Prior studies identified distinct chromosomal binding profiles for each TF despite their recognizing overlapping DNA motifs. The present study shows that Cmr binding specificity is determined by discriminator nucleotides at motif positions 4 and 13. X-ray crystallography and targeted mutational analyses identified an arginine-rich loop that expands Cmr's DNA interactions beyond the classical helix-turn-helix contacts common to all CRP/FNR family members and facilitates binding to imperfect DNA sequences. Cmr binding to DNA results in a pronounced asymmetric bending of the DNA and its high level of cooperativity is consistent with DNA-facilitated dimerization. A unique N-terminal extension inserts between the DNA binding and dimerization domains, partially occluding the site where the canonical cAMP binding pocket is found. However, an unstructured region of this N-terminus may help modulate Cmr activity in response to cellular signals. Cmr's multiple levels of DNA interaction likely enhance its ability to integrate diverse gene regulatory signals, while its novel structural features establish Cmr as an atypical CRP/FNR family member.

PubMed: 29165665
DOI: 10.1093/nar/gkx1148

実験手法

X-RAY DIFFRACTION (1.85 Å)