| pubmed-article:7893673 | rdf:type | pubmed:Citation | lld:pubmed |
| pubmed-article:7893673 | lifeskim:mentions | umls-concept:C0013682 | lld:lifeskim |
| pubmed-article:7893673 | lifeskim:mentions | umls-concept:C0600306 | lld:lifeskim |
| pubmed-article:7893673 | pubmed:issue | 11 | lld:pubmed |
| pubmed-article:7893673 | pubmed:dateCreated | 1995-4-27 | lld:pubmed |
| pubmed-article:7893673 | pubmed:abstractText | A posttranslationally methylated asparagine residue, N5-methylasparagine, is found at the beta-72 site in many phycobiliproteins. Two mutations (Asp and Gln) in the beta-72 position of Agmenellum quadruplicatum C-phycocyanin were investigated to clarify the role of the wild-type N5-methylasparagine near the beta-84 "fluorescing" bilin tetrapyrrole chromophore. Chemical analysis for amide modification revealed that the beta-72Q protein was partially methylated with a stoichiometry of 0.27, suggesting that either the asparagine methyltransferase is nonspecific or a glutamine methyltransferase exists. Urea denaturation studies could detect no difference in protein stability for any of the C-phycocyanin species. Steady-state spectroscopic measurements demonstrate that Asp and Gln substitution for the C-phycocyanin beta-72 NMA affects both the ground to excited state transition and the excited-state characteristics of the beta-84 chromophore, while the rate of radiative energy transfer is unaffected. Energy-transfer efficiency within phycobilisomes (represented by steady-state fluorescence quantum yields) was also negatively impacted by the beta-72 substitutions. Time-resolved fluorescence emission spectroscopic studies with C-phycocyanin reveal three distinguishable fluorescence lifetimes. The longest fluorescence lifetime is diminished 7-10% by the Asp and Gln mutations in comparison to a control sample where beta-72 is NMA. Molecular dynamics calculations implicate a change in the bilin tetrapyrrole chromophore ring geometry as a likely source of the altered photophysics induced by the mutations. We conclude that N5-methylasparagine plays a special role in establishing the environment surrounding the beta-84 chromophore which minimizes the rates of nonradiative energy losses that would otherwise defeat the high quantum yield for energy transfer within the phycobilisomes. | lld:pubmed |
| pubmed-article:7893673 | pubmed:language | eng | lld:pubmed |
| pubmed-article:7893673 | pubmed:journal | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:7893673 | pubmed:citationSubset | IM | lld:pubmed |
| pubmed-article:7893673 | pubmed:chemical | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:7893673 | pubmed:chemical | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:7893673 | pubmed:chemical | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:7893673 | pubmed:chemical | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:7893673 | pubmed:status | MEDLINE | lld:pubmed |
| pubmed-article:7893673 | pubmed:month | Mar | lld:pubmed |
| pubmed-article:7893673 | pubmed:issn | 0006-2960 | lld:pubmed |
| pubmed-article:7893673 | pubmed:author | pubmed-author:KlotzA VAV | lld:pubmed |
| pubmed-article:7893673 | pubmed:author | pubmed-author:ThomasB ABA | lld:pubmed |
| pubmed-article:7893673 | pubmed:author | pubmed-author:McMahonL PLP | lld:pubmed |
| pubmed-article:7893673 | pubmed:issnType | Print | lld:pubmed |
| pubmed-article:7893673 | pubmed:day | 21 | lld:pubmed |
| pubmed-article:7893673 | pubmed:volume | 34 | lld:pubmed |
| pubmed-article:7893673 | pubmed:geneSymbol | cpcC | lld:pubmed |
| pubmed-article:7893673 | pubmed:geneSymbol | cpcBA | lld:pubmed |
| pubmed-article:7893673 | pubmed:owner | NLM | lld:pubmed |
| pubmed-article:7893673 | pubmed:authorsComplete | Y | lld:pubmed |
| pubmed-article:7893673 | pubmed:pagination | 3758-70 | lld:pubmed |
| pubmed-article:7893673 | pubmed:dateRevised | 2006-11-15 | lld:pubmed |
| pubmed-article:7893673 | pubmed:meshHeading | pubmed-meshheading:7893673-... | lld:pubmed |
| pubmed-article:7893673 | pubmed:meshHeading | pubmed-meshheading:7893673-... | lld:pubmed |
| pubmed-article:7893673 | pubmed:meshHeading | pubmed-meshheading:7893673-... | lld:pubmed |
| pubmed-article:7893673 | pubmed:meshHeading | pubmed-meshheading:7893673-... | lld:pubmed |
| pubmed-article:7893673 | pubmed:meshHeading | pubmed-meshheading:7893673-... | lld:pubmed |
| pubmed-article:7893673 | pubmed:meshHeading | pubmed-meshheading:7893673-... | lld:pubmed |
| pubmed-article:7893673 | pubmed:meshHeading | pubmed-meshheading:7893673-... | lld:pubmed |
| pubmed-article:7893673 | pubmed:meshHeading | pubmed-meshheading:7893673-... | lld:pubmed |
| pubmed-article:7893673 | pubmed:meshHeading | pubmed-meshheading:7893673-... | lld:pubmed |
| pubmed-article:7893673 | pubmed:year | 1995 | lld:pubmed |
| pubmed-article:7893673 | pubmed:articleTitle | N5-methylasparagine and energy-transfer efficiency in C-phycocyanin. | lld:pubmed |
| pubmed-article:7893673 | pubmed:affiliation | Department of Biochemistry, Louisiana State University, Baton Rouge 70803. | lld:pubmed |
| pubmed-article:7893673 | pubmed:publicationType | Journal Article | lld:pubmed |
| pubmed-article:7893673 | pubmed:publicationType | Research Support, U.S. Gov't, Non-P.H.S. | lld:pubmed |
| http://linkedlifedata.com/r... | pubmed:referesTo | pubmed-article:7893673 | lld:pubmed |
| http://linkedlifedata.com/r... | pubmed:referesTo | pubmed-article:7893673 | lld:pubmed |
| http://linkedlifedata.com/r... | pubmed:referesTo | pubmed-article:7893673 | lld:pubmed |
