Linked Life Data

2167129

Source:http://linkedlifedata.com/resource/pubmed/id/2167129

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
23
pubmed:dateCreated
1990-9-27
pubmed:abstractText
Solid-state 13C MAS NMR spectra were obtained for dark-adapted bacteriorhodopsin (bR) labeled with [4'-13C]Tyr. Difference spectra (labeled minus natural abundance) taken at pH values between 2 and 12, and temperatures between 20 and -90 degrees C, exhibit a single signal centered at 156 ppm, indicating that the 11 tyrosines are protonated over a wide pH range. However, at pH 13, a second line appears in the spectrum with an isotropic shift of 165 ppm. Comparisons with solution and solid-state spectra of model compounds suggest that this second line is due to the formation of tyrosinate. Integrated intensities indicate that about half of the tyrosines are deprotonated at pH 13. This result demonstrates that deprotonated tyrosines in a membrane protein are detectable with solid-state NMR and that neither the bR568 nor the bR555 form of bR present in the dark-adapted state contains a tyrosinate at pH values between 2 and 12. Deprotonation of a single tyrosine in bR568 would account for 3.6% of the total tyrosine signal, which would be detectable with the current signal-to-noise ratio. We observe a slight heterogeneity and subtle line-width changes in the tyrosine signal between pH 7 and pH 12, which we interpret to be due to protein environmental effects (such as changes in hydrogen bonding) rather than complete deprotonation of tyrosine residue(s).
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
12
pubmed:volume
29
pubmed:owner
NLM
pubmed:authorsComplete
N
pubmed:pagination
5567-74
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Solid-state 13C NMR study of tyrosine protonation in dark-adapted bacteriorhodopsin.
pubmed:affiliation
Francis Bitter National Magnet Laboratory, Massachusetts Institute of Technology, Cambridge 02139.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't