Linked Life Data

12146964

Source:http://linkedlifedata.com/resource/pubmed/id/12146964

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
31
pubmed:dateCreated
2002-7-30
pubmed:abstractText
The SRPK family is distinguished from typical eukaryotic protein kinases by several unique structural features recently elucidated by X-ray diffraction methods [Nolen et al. (2001) Nat. Struct. Biol. 8, 176-183]. To determine whether these features impart unique catalytic function, the phosphorylation of the physiological Sky1p substrate, Npl3p, was monitored using steady-state and pre-steady-state kinetic techniques. While Sky1p has a low apparent affinity for ATP compared to other protein kinases, it binds Npl3p with very high affinity. The latter is achieved through a combination of local and distal factors in the protein substrate. The phosphoryl donor ATP has access to the nucleotide pocket in the absence or presence of Npl3p, indicating that a large protein substrate does not enforce an ordered addition of ligands. Sky1p binds two Mg(2+)-the first is essential whereas the second further enhances catalysis. While the turnover number is low (0.5 s(-1)), Npl3p is rapidly phosphorylated in the active site (40 s(-1)) based on single turnover experiments. These results indicate that Sky1p employs a catalytic pathway involving fast phosphoryl transfer followed by slow net release of products. These studies represent the first kinetic investigation of a member of the SRPK family and the first pre-steady-state kinetic study of a protein kinase using a natural protein substrate.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
6
pubmed:volume
41
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10002-9
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Mechanistic insights into Sky1p, a yeast homologue of the mammalian SR protein kinases.
pubmed:affiliation
Department of Chemistry and Biochemistry, University of California-San Diego, La Jolla, CA 92093, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't