title: The Ku-Mar zinc finger: A segment-swapped zinc ribbon in MarR-like transcription regulators related to the Ku bridge.
creator: Kaur, Gurmeet
creator: Subramanian, Srikrishna
subject: QR Microbiology
description: Two putative oxidative-stress sensor proteins from Pseudomonas aeruginosa, PA1607 and PA1374, belong to the MarR family of transcription regulators and possess a unique mode of dimerization. In these proteins, in addition to the α-helices involved in dimerization, inter-subunit contacts are strengthened by additional C-terminal β-strands. Using sequence and structure analysis we show that these β-strands constitute a novel segment-swapped zinc ribbon domain. We detect the presence of the zinc ribbon domain in MarR proteins from many bacterial homologs. While the metal-chelating residues of the zinc ribbons are absent in most members of this family, we could however identify several species of Proteobacteria, Actinobacteria and Firmicutes that possess intact zinc-chelating sites. Conservation pattern of metal-chelating residues together with the extensive structural resemblance to zinc ribbons, in particular to the bridge-region of the dsDNA break repair protein Ku, suggests that the C-terminal β-rich region of these proteins is a zinc ribbon. Sequence analysis also supports a distant evolutionary connection between the zinc ribbons of the MarR and Ku families. However, unlike Ku where the segment-swapped zinc ribbons play a role in DNA-binding and obligate dimerization, their primary role in MarR appears to be in dimerization and strengthening of inter-subunit contacts.
publisher: Elsevier Science
date: 2015-09
type: Article
type: PeerReviewed
relation: http://www.sciencedirect.com/science/article/pii/S1047847715300368
identifier:   Kaur, Gurmeet and Subramanian, Srikrishna  (2015) The Ku-Mar zinc finger: A segment-swapped zinc ribbon in MarR-like transcription regulators related to the Ku bridge.  Journal of structural biology, 191 (3).  pp. 281-9.  ISSN 1095-8657     
relation: http://crdd.osdd.net/open/1761/