Linked Life Data

12220175

Source:http://linkedlifedata.com/resource/pubmed/id/12220175

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
37
pubmed:dateCreated
2002-9-10
pubmed:abstractText
The Escherichia coli protein YjeQ represents a protein family whose members are broadly conserved in bacteria and have been shown to be indispensable to the growth of E. coli and Bacillus subtilis [Arigoni, F., et al. (1998) Nat. Biotechnol. 16, 851]. Proteins of the YjeQ family contain all sequence motifs typical of the vast class of P-loop-containing GTPases, but show a circular permutation, with a G4-G1-G3 pattern of motifs as opposed to the regular G1-G3-G4 pattern seen in most GTPases. All YjeQ family proteins display a unique domain architecture, which includes a predicted N-terminal OB-fold RNA-binding domain, the central permuted GTPase module, and a zinc knuckle-like C-terminal cysteine cluster. This domain architecture suggests a possible role for YjeQ as a regulator of translation. YjeQ was overexpressed, purified to homogeneity, and shown to contain 0.6 equiv of GDP. Steady state kinetic analyses indicated slow GTP hydrolysis, with a k(cat) of 9.4 h(-)(1) and a K(m) for GTP of 120 microM (k(cat)/K(m) = 21.7 M(-)(1) s(-)(1)). YjeQ also hydrolyzed other nucleoside triphosphates and deoxynucleotide triphosphates such as ATP, ITP, and CTP with specificity constants (k(cat)/K(m)) ranging from 0.2 to 1.0 M(-)(1) s(-)(1). Pre-steady state kinetic analysis of YjeQ revealed a burst of nucleotide hydrolysis for GTP described by a first-order rate constant of 100 s(-)(1) as compared to a burst rate of 0.2 s(-)(1) for ATP. In addition, a variant in the G1 motif of YjeQ (S221A) was substantially impaired for GTP hydrolysis (0.3 s(-)(1)) with a less significant impact on the steady state rate (1.8 h(-)(1)). In summary, E. coli YjeQ is an unusual, circularly permuted P-loop-containing GTPase, which catalyzes GTP hydrolysis at a rate 45 000 times greater than that of turnover.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
17
pubmed:volume
41
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11109-17
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:12220175-Amino Acid Motifs, pubmed-meshheading:12220175-Amino Acid Sequence, pubmed-meshheading:12220175-Catalysis, pubmed-meshheading:12220175-Conserved Sequence, pubmed-meshheading:12220175-Escherichia coli, pubmed-meshheading:12220175-Escherichia coli Proteins, pubmed-meshheading:12220175-GTP Phosphohydrolases, pubmed-meshheading:12220175-Guanosine Triphosphate, pubmed-meshheading:12220175-Heterotrimeric GTP-Binding Proteins, pubmed-meshheading:12220175-Hydrolysis, pubmed-meshheading:12220175-Kinetics, pubmed-meshheading:12220175-Molecular Sequence Data, pubmed-meshheading:12220175-Peptide Fragments, pubmed-meshheading:12220175-Protein Binding, pubmed-meshheading:12220175-Recombinant Proteins, pubmed-meshheading:12220175-Sequence Homology, Amino Acid, pubmed-meshheading:12220175-Substrate Specificity
pubmed:year
2002
pubmed:articleTitle
YjeQ, an essential, conserved, uncharacterized protein from Escherichia coli, is an unusual GTPase with circularly permuted G-motifs and marked burst kinetics.
pubmed:affiliation
Antimicrobial Research Centre, Department of Biochemistry, McMaster University, Hamilton, Ontario, Canada L8N 3Z5.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't