Linked Life Data

18514735

Source:http://linkedlifedata.com/resource/pubmed/id/18514735

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2008-6-16
pubmed:abstractText
The ribosomal stalk complex in Escherichia coli consists of L10 and four copies of L7/L12, and is largely responsible for binding and recruiting translation factors. Structural characterisation of this stalk complex is difficult, primarily due to its dynamics. Here, we apply mass spectrometry to follow post-translational modifications and their effect on structural changes of the stalk proteins on intact ribosomes. Our results show that increased acetylation of L12 occurs during the stationary phase on ribosomes harvested from cells grown under optimal conditions. For cells grown in minimal medium, L12 acetylation and processing is altered, resulting in deficient removal of N-terminal methionine in approximately 50% of the L12 population, while processed L12 is almost 100% acetylated. Our results show also that N-acetylation of L12 correlates with an increased stability of the stalk complex in the gas phase. To investigate further the basis of this increased stability, we applied a solution phase hydrogen deuterium exchange protocol to compare the rate of deuterium incorporation in the proteins L9, L10, L11 and L12 as well as the acetylated form of L12 (L7), in situ on the ribosome. Results show that deuterium incorporation is consistently slower for L7 relative to L12 and for L10 when L7 is predominant. Our results imply a tightening of the interaction between L7 and L10 relative to that between L12 and L10. Since acetylation is predominant when cells are grown in minimal medium, we propose that these modifications form part of the cell's strategy to increase stability of the stalk complex under conditions of stress. More generally, our results demonstrate that it is possible to discern the influence of a 42 Da post-translational modification by mass spectrometry and to record subtle changes in hydrogen/deuterium exchange within the context of an intact 2.5 MDa particle.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1089-8638
pubmed:author
pubmed:issnType
Electronic
pubmed:day
4
pubmed:volume
380
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
404-14
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Acetylation of L12 increases interactions in the Escherichia coli ribosomal stalk complex.
pubmed:affiliation
Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't