title: The low-molecular-mass subunit of the cell wall channel of the Gram-positive Corynebacterium glutamicum. Immunological localization, cloning and sequencing of its gene porA.
abstract: The 5-kDa protein PorA of the Gram-positive bacterium Corynebacterium glutamicum is the subunit of the cell wall channel. Antibodies raised against PorA specifically detected the protein on the cell surface. PorA was sequenced using Edman degradation and a gas phase sequencer. The primary sequence was used to create degenerate oligonucleotide primers. The gene of the channel-forming protein and its flanking regions were obtained by PCR followed by inverse PCR. The gene porA comprises 138 bp and encodes a 45-amino-acid-long acidic polypeptide with an excess of four negatively charged amino acids in agreement with the high cation selectivity of the PorA cell wall channel. PorA does not contain an N-terminal extension. A ribosomal-binding site was recognized 6 bp before the start codon ATG of porA. It codes for the smallest subunit of a membrane channel known so far and for the first cell wall channel protein of a corynebacterium. Southern blots demonstrated that only the chromosomes of corynebacteria contain homologous sequences to porA; no hybridization could be detected with DNA from other mycolata.
authors.affiliation: Lehrstuhl für Biotechnologie, Biozentrum der Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Lichtinger
authors.forename: F G
authors.initials: FG
authors.lastname: Riess
authors.forename: A
authors.initials: A
authors.lastname: Burkovski
authors.forename: F
authors.initials: F
authors.lastname: Engelbrecht
authors.forename: D
authors.initials: D
authors.lastname: Hesse
authors.forename: H D
authors.initials: HD
authors.lastname: Kratzin
authors.forename: R
authors.initials: R
authors.lastname: Krämer
authors.forename: R
authors.initials: R
authors.lastname: Benz
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport; D002473:Cell Wall / Q000737:chemistry / Q000235:genetics*; D003001:Cloning, Molecular; D003352:Corynebacterium / Q000235:genetics*; D005798:Genes, Bacterial; D018698:Glutamic Acid / Q000096:biosynthesis; D007218:Industrial Microbiology; D008969:Molecular Sequence Data; D009171:Mycolic Acids; D016133:Polymerase Chain Reaction; D018272:Porins / Q000235:genetics* / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: D009171:Mycolic Acids; C422458:PorA protein, Corynebacterium glutamicum; D018272:Porins; D018698:Glutamic Acid