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Free keywords:
Amino Acid Sequence; *Bacteria, Aerobic/ge [Genetics]; *Bacterial Outer Membrane Proteins/ge [Genetics]; Base Sequence; Blotting, Southern; *Cloning, Molecular; Comparative Study; *Escherichia coli/ge [Genetics]; *Gene Expression; *Genes, Structural, Bacterial; *Gram-Positive Bacteria/ge [Genetics]; Molecular Sequence Data; Nucleic Acid Hybridization; Plasmids; Restriction Mapping; Sequence Homology, Nucleic Acid; Support, Non-U.S. Gov't; Temperature
Abstract:
Acetogenium kivui is anaerobically growing thermophilic bacterium with a gram-positive type of cell wall structure. The outer surface is covered with a hexagonally packed surface (S) layer. The gene coding for the S-layer polypeptide was cloned in Escherichia coli on two overlapping fragments by using the plasmid pUC18 as the vector. It was expressed under control of a cloned Acetogenium promoter or the lacZ gene. We determined the complete sequence of the structural gene. The mature polypeptide comprises 736 amino acids and is preceded by a typical procaryotic signal sequence of 26 amino acids. It i weakly acidic, weakly hydrophilic, and contains a relatively high proportion of hydroxyamino acids, including two clusters of serine and threonine residues. An N-terminal region of about 200 residues is homologous to the N-terminal part of the middle wall protein, one of the two S-layer proteins of Bacillus brevis, and there is also an internal homology within the N-terminal region of the A. kivui polypeptide.
