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Title: Functional and immunochemical characterization of a mutant of Escherichia coli energy uncoupled for lactose transport

Abstract

Right-side-out cytoplasmic membrane vesicles from Escherichia coli ML 308-22, a mutant ''uncoupled'' for beta-galactoside/H/sup +/ symport are specifically defective in the ability to catalyze accumulation of methyl 1-thio-beta-D-galactopyranoside (TMG) in the presence of an H/sup +/ electrochemical gradient (interior negative and alkaline). Furthermore, the rate of carrier-mediated efflux under nonenergized conditions is slow and unaffected by ambient pH from pH 5.5 to 7.5, and TMG-induced H/sup +/ influx is only about 15% of that observed in vesicles containing wild-type lac permease (ML 308-225). Alternatively, ML 308-22 vesicles bind p-nitrophenyl alpha-D-galactopyranoside and monoclonal antibody 4B1 to the same extent as ML 308-225 vesicles and catalyze facilitated diffusion and equilibrium exchange as well as ML 308-225 vesicles. When entrance counterflow is studied with external substrate at saturating and subsaturating concentrations, it is apparent that the mutation simulates the effects of deuterium oxide. That is, the mutation has no effect on the rate or extent of counterflow when external substrate is saturating but stimulates the efficiency of counterflow when external substrate is below the apparent K/sub m/. Moreover, although replacement of protium with deuterium stimulates counterflow in ML 308-225 vesicles when external substrate is subsaturating, the isotope has no effect on the mutantmore » vesicles under the same conditions.« less

Authors:
; ;
Publication Date:
OSTI Identifier:
5023278
Resource Type:
Journal Article
Journal Name:
Biochemistry; (United States)
Additional Journal Information:
Journal Volume: 1
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; LACTOSE; MEMBRANE TRANSPORT; MEMBRANE PORES; BIOCHEMICAL REACTION KINETICS; CARBON ISOTOPES; CELL MEMBRANES; DEUTERIUM COMPOUNDS; ESCHERICHIA COLI; KINETICS; MONOCLONAL ANTIBODIES; MONOSACCHARIDES; MUTANTS; PH VALUE; PROLINE; TRACER TECHNIQUES; AMINES; AMINO ACIDS; ANTIBODIES; AZOLES; BACTERIA; CARBOHYDRATES; CARBOXYLIC ACIDS; CELL CONSTITUENTS; DISACCHARIDES; HETEROCYCLIC ACIDS; HETEROCYCLIC COMPOUNDS; HYDROGEN COMPOUNDS; ISOTOPE APPLICATIONS; ISOTOPES; MEMBRANES; MICROORGANISMS; OLIGOSACCHARIDES; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; PYRROLES; PYRROLIDINES; REACTION KINETICS; SACCHARIDES; 550201* - Biochemistry- Tracer Techniques

Citation Formats

Herzlinger, D, Carrasco, N, and Kaback, H R. Functional and immunochemical characterization of a mutant of Escherichia coli energy uncoupled for lactose transport. United States: N. p., 1985. Web. doi:10.1021/bi00322a032.
Herzlinger, D, Carrasco, N, & Kaback, H R. Functional and immunochemical characterization of a mutant of Escherichia coli energy uncoupled for lactose transport. United States. https://doi.org/10.1021/bi00322a032
Herzlinger, D, Carrasco, N, and Kaback, H R. 1985. "Functional and immunochemical characterization of a mutant of Escherichia coli energy uncoupled for lactose transport". United States. https://doi.org/10.1021/bi00322a032.
@article{osti_5023278,
title = {Functional and immunochemical characterization of a mutant of Escherichia coli energy uncoupled for lactose transport},
author = {Herzlinger, D and Carrasco, N and Kaback, H R},
abstractNote = {Right-side-out cytoplasmic membrane vesicles from Escherichia coli ML 308-22, a mutant ''uncoupled'' for beta-galactoside/H/sup +/ symport are specifically defective in the ability to catalyze accumulation of methyl 1-thio-beta-D-galactopyranoside (TMG) in the presence of an H/sup +/ electrochemical gradient (interior negative and alkaline). Furthermore, the rate of carrier-mediated efflux under nonenergized conditions is slow and unaffected by ambient pH from pH 5.5 to 7.5, and TMG-induced H/sup +/ influx is only about 15% of that observed in vesicles containing wild-type lac permease (ML 308-225). Alternatively, ML 308-22 vesicles bind p-nitrophenyl alpha-D-galactopyranoside and monoclonal antibody 4B1 to the same extent as ML 308-225 vesicles and catalyze facilitated diffusion and equilibrium exchange as well as ML 308-225 vesicles. When entrance counterflow is studied with external substrate at saturating and subsaturating concentrations, it is apparent that the mutation simulates the effects of deuterium oxide. That is, the mutation has no effect on the rate or extent of counterflow when external substrate is saturating but stimulates the efficiency of counterflow when external substrate is below the apparent K/sub m/. Moreover, although replacement of protium with deuterium stimulates counterflow in ML 308-225 vesicles when external substrate is subsaturating, the isotope has no effect on the mutant vesicles under the same conditions.},
doi = {10.1021/bi00322a032},
url = {https://www.osti.gov/biblio/5023278}, journal = {Biochemistry; (United States)},
number = ,
volume = 1,
place = {United States},
year = {Tue Jan 01 00:00:00 EST 1985},
month = {Tue Jan 01 00:00:00 EST 1985}
}