Biomaterial Database

The light-harvesting polypeptides of Rhodopseudomonas viridis. The complete amino-acid sequences of B1015-alpha, B1015-beta and B1015-gamma. 1985

R A Brunisholz, and F Jay, and F Suter, and H Zuber

Three low molecular mass polypeptides have been isolated by using the technique of organic solvent extraction of thylakoid membranes or whole cells from Rhodopseudomonas viridis. Their primary structures were determined by long liquid phase sequencer runs, combined with the isolation and sequence analysis of the C-terminal o-iodosobenzoic acid fragment and carboxypeptidase degradation. The polypeptide which consists of 58 amino-acids and is 46% homologous to the antenna polypeptide B880-alpha from Rhodospirillum rubrum was designated as B1015-alpha (1 His residue). The sequence homology between the second polypeptide, named B1015-beta (55 amino acids, 2 His residues) and B880-beta from Rs. rubrum is 52%. For the third polypeptide consisting of 36 amino acids and exhibiting a high hydrophobicity, no equivalent polypeptide has so far been found in other purple bacteria. The molar ratio of these three organic solvent soluble polypeptides from Rp. viridis was estimated to be 1:1:1. Accordingly, the 36 amino-acid polypeptide is likely to be an additional constituent of the light-harvesting complex B1015, consequently termed as B1015-gamma. According to hydrophathy profiles, the transmembrane arrangement of B1015-alpha and B1015-beta within the thylakoid membrane is supposed to be similar. B1015-gamma, however, shows a somewhat different hydropathy profile. A particular feature of this polypeptide is its high amount of aromatic amino acids. It is postulated that B1015-gamma is involved in the formation of regular arrays of light-harvesting complexes.

UI	MeSH Term	Description	Entries
D008566	Membranes	Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.	Membrane Tissue,Membrane,Membrane Tissues,Tissue, Membrane,Tissues, Membrane
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D010455	Peptides	Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are considered to be larger versions of peptides that can form into complex structures such as ENZYMES and RECEPTORS.	Peptide,Polypeptide,Polypeptides
D006868	Hydrolysis	The process of cleaving a chemical compound by the addition of a molecule of water.
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D000596	Amino Acids	Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.	Amino Acid,Acid, Amino,Acids, Amino
D001426	Bacterial Proteins	Proteins found in any species of bacterium.	Bacterial Gene Products,Bacterial Gene Proteins,Gene Products, Bacterial,Bacterial Gene Product,Bacterial Gene Protein,Bacterial Protein,Gene Product, Bacterial,Gene Protein, Bacterial,Gene Proteins, Bacterial,Protein, Bacterial,Proteins, Bacterial
D012241	Rhodopseudomonas	A genus of gram-negative, rod-shaped, phototrophic bacteria found in aquatic environments. Internal photosynthetic membranes are present as lamellae underlying the cytoplasmic membrane.
D045322	Photosynthetic Reaction Center Complex Proteins	Protein complexes that take part in the process of PHOTOSYNTHESIS. They are located within the THYLAKOID MEMBRANES of plant CHLOROPLASTS and a variety of structures in more primitive organisms. There are two major complexes involved in the photosynthetic process called PHOTOSYSTEM I and PHOTOSYSTEM II.	Photosynthetic Complex,Photosynthetic Reaction Center,Photosynthetic Reaction Center Complex Protein,Photosynthetic Complexes,Photosynthetic Reaction Centers,Center, Photosynthetic Reaction,Complex, Photosynthetic,Complexes, Photosynthetic,Reaction Center, Photosynthetic,Reaction Centers, Photosynthetic