Linked Life Data

10842177

Source:http://linkedlifedata.com/resource/pubmed/id/10842177

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
44
pubmed:dateCreated
2000-11-20
pubmed:abstractText
The lactose transport protein (LacS) of Streptococcus thermophilus is composed of a translocator domain and a regulatory domain that is phosphorylated by HPr(His approximately P), the general energy coupling protein of the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS). Lactose transport is affected by the phosphorylation state of HPr through changes in the activity of the LacS protein as well as expression of the lacS gene. To address whether or not CcpA-HPr(Ser-P)-mediated catabolite control is involved, the levels of LacS were determined under conditions in which the cellular phosphorylation state of HPr greatly differed. It appears that HPr(Ser-P) is mainly present in the exponential phase of growth, whereas HPr(His approximately P) dominates in the stationary phase. The transition from HPr(Ser-P) to HPr(His approximately P) parallels an increase in LacS level, a drop in lactose and an increase in galactose concentration in the growth medium. Because the K(m)(out) for lactose is higher than that for galactose, the lactose transport capacity decreases as lactose concentration decreases and galactose accumulates in the medium. Our data indicate that S. thermophilus compensates for the diminished transport capacity by synthesizing more LacS and phosphorylating the protein, which results in increased transport activity. The link between transport capacity and lacS expression levels and LacS phosphorylation are discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
3
pubmed:volume
275
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
34073-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Phosphorylation state of HPr determines the level of expression and the extent of phosphorylation of the lactose transport protein of Streptococcus thermophilus.
pubmed:affiliation
Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't