Linked Life Data

2765055

Source:http://linkedlifedata.com/resource/pubmed/id/2765055

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5-6
pubmed:dateCreated
1989-9-28
pubmed:abstractText
The topography of chloroplast cytochromes f and b6 was probed with proteases carboxypeptidase A (CpA), trypsin, and Staph, aureus V8. The cytochrome and its proteolytic products were detected by heme stain and, in most experiments, by immunoreaction. In thylakoids, the only protease that significantly affected the intactness of cytochrome f was CpA that caused a small (delta Mr = -1-2000) decrease in the apparent molecular weight. In SDS-treated thylakoids, both trypsin and V8 degraded cytochrome f. The inferred topography of cytochrome f., with the COOH-terminus on the stromal (n) side, one membrane-spanning alpha-elix near the COOH-terminus, and most of the Cyt f mass on the lumen (p) side, is consistent with that previously inferred by others. Cytochrome b6 was not sensitive to CpA, but was more sensitive to trypsin and V8 protease than cytochrome f, cytochrome b-559, or the 17 kDa OEC extrinsic protein. Trypsin caused a small decrease in size of cytochrome b6, which was observed using whole protein antibody as a single smaller band (delta Mr approximately 2000) or two smaller discrete bands (delta Mr = -1000 and 2500, respectively) which, unlike the untreated protein, did not react with antibody generated to a peptide mimicking Asp-5-Gln-14 near the NH2-terminus. These shortened tryptic fragments were attributed to cleavage after R-10 and K-23 near the NH2-terminus, implying an orientation with the NH2-terminus on the stromal side of the membrane. The sensitivity of cytochrome b6 toward this trypsin cleavage was increased if the membranes were first incubated with CpA, showing that the NH2-terminal region of cytochrome b6 is masked by the COOH-terminal domain of one or more thylakoid proteins.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0939-5075
pubmed:author
pubmed:issnType
Print
pubmed:volume
44
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
453-61
pubmed:dateRevised
2009-11-4
pubmed:meshHeading
pubmed:articleTitle
Topography of the chloroplast cytochrome b6: orientation of the cytochrome and accessibility of the lumen-side interhelix loops.
pubmed:affiliation
Department of Biological Sciences, Purdue University, West Lafayette, IN 47907.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.