Linked Life Data

20923236

Source:http://linkedlifedata.com/resource/pubmed/id/20923236

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
45
pubmed:dateCreated
2010-11-9
pubmed:abstractText
Conformational switching upon core RNA polymerase binding is an integral part of functioning of bacterial sigma factors. Here, we have studied dynamical features of two alternative sigma factors. A study of fluorescence resonance energy transfer and hydrodynamic measurements in Escherichia coli ?(32) suggest a compact shape like those found in complex with anti-sigma factors. On the other hand, the fluorescence anisotropy of probes attached to different regions of the protein and previous hydrogen exchange measurements suggest significant internal flexibility, particularly in the C-terminal half and region 1. In a homologous sigma factor, ?(F) of Mycobacterium tuberculosis, emission spectra and fluorescence resonance energy transfer between the single tryptophan (W112) and probes placed in different regions suggest a compact conformation for a major part of the N-terminal half encompassing region 2 and the flexible C-terminal half. Fluorescence anisotropy measurements suggest significant flexibility in the C-terminal half and region 1, as well. Thus, free alternative sigma factors may be in equilibrium between two conformations: a compact one in which the promoter interacting motifs are trapped in the wrong conformation and another less abundant one with a more open and flexible conformation. Such flexibility may be important for promoter recognition and interaction with many partner proteins.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1520-4995
pubmed:author
pubmed:issnType
Electronic
pubmed:day
16
pubmed:volume
49
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
9809-19
pubmed:meshHeading
pubmed-meshheading:20923236-Ampicillin, pubmed-meshheading:20923236-Carbenicillin, pubmed-meshheading:20923236-Cloning, Molecular, pubmed-meshheading:20923236-DNA-Directed RNA Polymerases, pubmed-meshheading:20923236-Dithionitrobenzoic Acid, pubmed-meshheading:20923236-Dithiothreitol, pubmed-meshheading:20923236-Edetic Acid, pubmed-meshheading:20923236-Fluorescence Polarization, pubmed-meshheading:20923236-Kanamycin, pubmed-meshheading:20923236-Kinetics, pubmed-meshheading:20923236-Mutagenesis, Site-Directed, pubmed-meshheading:20923236-Naphthalenesulfonates, pubmed-meshheading:20923236-Phenylmethylsulfonyl Fluoride, pubmed-meshheading:20923236-Protein Binding, pubmed-meshheading:20923236-Protein Conformation, pubmed-meshheading:20923236-Restriction Mapping, pubmed-meshheading:20923236-Sigma Factor
pubmed:year
2010
pubmed:articleTitle
Alternative sigma factors in the free state are equilibrium mixtures of open and compact conformations.
pubmed:affiliation
Department of Structural Biology and Bioinformatics, Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata 700 032, India.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't