Biomaterial Database

Membrane topography of the photosynthetic reaction center polypeptides of Rhodopseudomonas sphaeroides. 1981

R C Bachmann, and K Gillies, and J Y Takemoto

The topography of the photosynthetic reaction center (RC) polypeptides (H, M, and L) was investigated by proteolysis and radioiodination of membrane vesicles isolated from Rhodopseudomonas sphaeroides. Chromatophores, obtained from French-pressed cell lysates, are closed vesicles' and oriented inside out with respect to the cytoplasmic membrane (cytoplasmic side out). Spheroplast-derived vesicles (SDVs), obtained after osmotic lysis of lysozyme-treated cells, are oriented right side in (periplasmic side out). Alpha-Chymotrypsin treatment of chromatophores and trypsin treatment of SDVs resulted in cleavage of H. Alpha-Chymotrypsin treatment of SDVs did not cleave H, and trypsin treatment of chromatophores did not consistently cleave this polypeptide. M and L of both vesicles were apparently not affected by these proteases. The SDV trypsin cleavage product of H was identified by alpha-chymotryptic (125)I-labeled peptide mapping and had a molecular weight of 26 000. Membrane surface radioiodination with chloroglycoluril coated on glass tubes resulted in preferential labeling of H and M of SDVs and chromatophores. The radiospecific activities of H, M, and L were higher with labeling of SDVs as compared to labeling of chromatophores. Alpha-Chymotryptic (125)I-labeled peptide maps of H, M, and L from surface-radioiodinated SDVs differed from the corresponding maps of these polypeptides from surface-radioiodinated chromatophores. The results indicate the asymmetric exposure of H, M, and L on opposite surfaces of the R. sphaeroides membrane. Exposed iodination sites of these polypeptides are more abundant on the periplasmic surface than on the cytoplasmic surface of this membrane.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D010788	Photosynthesis	The synthesis by organisms of organic chemical compounds, especially carbohydrates, from carbon dioxide using energy obtained from light rather than from the oxidation of chemical compounds. Photosynthesis comprises two separate processes: the light reactions and the dark reactions. In higher plants; GREEN ALGAE; and CYANOBACTERIA; NADPH and ATP formed by the light reactions drive the dark reactions which result in the fixation of carbon dioxide. (from Oxford Dictionary of Biochemistry and Molecular Biology, 2001)	Calvin Cycle,Calvin-Benson Cycle,Calvin-Benson-Bassham Cycle,Carbon Fixation, Photosynthetic,Reductive Pentose Phosphate Cycle,Dark Reactions of Photosynthesis,Calvin Benson Bassham Cycle,Calvin Benson Cycle,Cycle, Calvin,Cycle, Calvin-Benson,Cycle, Calvin-Benson-Bassham,Photosynthesis Dark Reaction,Photosynthesis Dark Reactions,Photosynthetic Carbon Fixation
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D002918	Chymotrypsin	A serine endopeptidase secreted by the pancreas as its zymogen, CHYMOTRYPSINOGEN and carried in the pancreatic juice to the duodenum where it is activated by TRYPSIN. It selectively cleaves aromatic amino acids on the carboxyl side.	Alpha-Chymotrypsin Choay,Alphacutanée,Avazyme
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
D012242	Rhodobacter sphaeroides	Spherical phototrophic bacteria found in mud and stagnant water exposed to light.	Rhodopseudomonas sphaeroides,Rhodobacter spheroides,Rhodopseudomonas spheroides
D014357	Trypsin	A serine endopeptidase that is formed from TRYPSINOGEN in the pancreas. It is converted into its active form by ENTEROPEPTIDASE in the small intestine. It catalyzes hydrolysis of the carboxyl group of either arginine or lysine. EC 3.4.21.4.	Tripcellim,Trypure,beta-Trypsin,beta Trypsin
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