title: Calcium chloride made E. coli competent for uptake of extraneous DNA through overproduction of OmpC protein.
abstract: In the standard method of transformation of Escherichia coli with extraneous DNA, cells are made competent for DNA uptake by incubating in ice-cold 100 mM CaCl(2). Analysis of the whole protein profile of CaCl(2)-treated E. coli cells by the techniques of one- and two-dimensional gel electrophoresis, MALDI-MS and immunoprecipitation revealed overproduction of outer membrane proteins OmpC, OmpA and heat-shock protein GroEL. In parity, transformation efficiency of E. coli ompC mutant by plasmid pUC19 DNA was found to be about 40 % lower than that of the wild type strain. Moreover, in E. coli cells containing groEL-bearing plasmid, induction of GroEL caused simultaneous overproduction of OmpC. On the other hand, less OmpC was synthesized in E. coli groEL mutant compared to its wild type counterpart, by CaCl(2)-shock. From these results it can be suggested that in the process of CaCl(2)-mediated generation of competence, the heat-shock chaperone GroEL has specific role in DNA entry into the cell, possibly through the overproduced OmpC and OmpA porins.
authors.affiliation: Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, 741 235, West Bengal, India.
authors.forename: Pulakesh
authors.initials: P
authors.lastname: Aich
authors.forename: Monobesh
authors.initials: M
authors.lastname: Patra
authors.forename: Arijit Kumar
authors.initials: AK
authors.lastname: Chatterjee
authors.forename: Sourav Singha
authors.initials: SS
authors.lastname: Roy
authors.forename: Tarakdas
authors.initials: T
authors.lastname: Basu
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D001692:Biological Transport; D002122:Calcium Chloride / Q000378:metabolism*; D018834:Chaperonin 60 / Q000378:metabolism; D003080:Cold Temperature; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D018272:Porins / Q000378:metabolism*; D014176:Protein Biosynthesis; D014170:Transformation, Genetic
chemical_list: D001425:Bacterial Outer Membrane Proteins; D018834:Chaperonin 60; D029968:Escherichia coli Proteins; C113724:OmpC protein; D018272:Porins; C078167:OMPA outer membrane proteins; D004247:DNA; D002122:Calcium Chloride