Biomaterial Database

Time-resolved surface charge change on the cytoplasmic side of bacteriorhodopsin. 1995

U Alexiev, and P Scherrer, and T Marti, and H G Khorana, and M P Heyn

Biophysics Group, Freie Universität Berlin, Germany.

The pH-sensitive dye 5-iodoacetamidofluorescein was covalently bound to a single cysteine residue introduced by site-directed mutagenesis in position 101 on the cytoplasmic surface or in position 130 on the extracellular surface of the proton pump bacteriorhodopsin. Using time-resolved absorption spectroscopy at 495 nm a transient increase was observed in the apparent pK of the dye attached at residue 101. At pH 7.3 the rise and decay times of this pK-change (approximately 2 ms and approximately 60 ms) correlate well with decay times observed for the M and O intermediates and with the proton uptake time. Interpreting the pK-increase of +0.18 pH-unit in terms of a transiently more negative surface charge density, we calculate a change of -0.80 elementary charge per bacteriorhodopsin at the cytoplasmic surface. It is likely that this charge change is due to the transient deprotonation of aspartate-96. With the label in position 130 on the extracellular surface no transient pK-shift was detected.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D011199	Potentiometry	Solution titration in which the end point is read from the electrode-potential variations with the concentrations of potential determining ions. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
D011994	Recombinant Proteins	Proteins prepared by recombinant DNA technology.	Biosynthetic Protein,Biosynthetic Proteins,DNA Recombinant Proteins,Recombinant Protein,Proteins, Biosynthetic,Proteins, Recombinant DNA,DNA Proteins, Recombinant,Protein, Biosynthetic,Protein, Recombinant,Proteins, DNA Recombinant,Proteins, Recombinant,Recombinant DNA Proteins,Recombinant Proteins, DNA
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D003593	Cytoplasm	The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)	Protoplasm,Cytoplasms,Protoplasms
D004134	Dimyristoylphosphatidylcholine	A synthetic phospholipid used in liposomes and lipid bilayers for the study of biological membranes.	Dimyristoyllecithin,1,2-Dimyristoyl-glycero-3-phosphorylcholine,1,2-Ditetradecanoyl-glycero-3-phosphocholine,1,2-Ditetradecyl-glycero-3-phosphocholine,DMCP,DMPC,1,2 Dimyristoyl glycero 3 phosphorylcholine,1,2 Ditetradecanoyl glycero 3 phosphocholine,1,2 Ditetradecyl glycero 3 phosphocholine
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
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