English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Four low-molecular-mass polypeptides were isolated and purified from chromatophore membranes of Rhodopseudomonas sphaeroides blue-green mutant R-26.1 by a combination of gel filtration and ion-exchange chromatography in organic solvents. On dodecyl sulfate polyacrylamide gels, the purified polypeptides comigrate with bands LH-1, LH-2 and LH-3 known to be related to the antenna-pigment-protein complexes. The complete primary structures were elucidated by automated Edman degradation of the intact polypeptides and of overlapping C-terminal fragments obtained after chemical cleavage at tryptophan and methionine residues. The C-termini were verified by hydrazinolysis and, in one case where an overlapping C-terminal fragment could not be obtained, by digestion with carboxypeptidase A. The four polypeptides show a tripartite structure: i.e. a polar N-terminal region is separated from a polar C-terminal region by a segment of about 21 predominantly hydrophobic amino-acid residues. All hydrophobic segments contain a characteristic conservative histidine residue. The C-terminal region is reduced to only a few amino acids in the two polypeptides which together form band LH-3, i.e. LH-3A and LH-3B. Their extended N-terminal region is rich in charged residues and contains an additional conserved histidine residue close to the beginning of the hydrophobic segment. These properties place LH-3A and LH-3B into subgroup (beta-polypeptides: B 870-beta and B 850-beta, respectively). LH-1 and LH-2 appear to form another subgroup (alpha-polypeptides: B 870-alpha and B 850-alpha, respectively) as suggested during a search for conservative elements within their sequences (structural basis for classification). N-Terminal analyses carried out with intact antenna-pigment-protein complexes revealed the following: (i) LH-1 and LH-3 are associated with the B 870 complex in Rp. sphaeroides 24.1 (wild type), (ii) the same polypeptides are almost exclusively present in chromatophore membranes of Rp. sphaeroides R-26, a blue-green mutant which absorbs at 870 nm, (iii) LH-2 and LH-3B are the constituent polypeptides of the B 800-850 complex of Rp. sphaeroides 2.4.1 and of the spectrally altered B 850 complex isolated from the blue-green mutant R-26.1 which absorbs at 860 nm. This mutant contains LH-2 and LH-3B along with LH-1 and LH-3A and apparently is able to form both types of antenna complexes.(ABSTRACT TRUNCATED AT 400 WORDS)

The Light-Harvesting Polypeptides of Rhodopseudomonas sphaeroides R-26.1. I. Isolation, Purification and Sequence Analyses