Identification of protein-protein contacts between alpha/beta-type small, acid-soluble spore proteins of Bacillus species bound to DNA.
Small, acid-soluble spore proteins (SASP) of the alpha/beta-type from several Bacillus species were cross-linked into homodimers, heterodimers and homooligomers with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) in the presence of linear plasmid DNA. Significant protein cross-linking was not detected in the absence of DNA. In all four alpha/beta-type SASP examined, the amino donor in the EDC induced amide cross-links was the alpha-amino group of the protein. However, the carboxylate containing amino acid residues involved in cross-linking varied. In SASP-A and SASP-C of Bacillus megaterium two conserved glutamate residues, which form part of the germination protease recognition sequence, were involved in cross-link formation. In SspC from Bacillus subtilis and Bce1 from Bacillus cereus the acidic residues involved in cross-link formation were not in the protease recognition sequence, but at a site closer to the N terminus of the proteins. These data indicate that, although there are likely to be subtle structural differences between different alpha/beta-type SASP, the N-terminal regions of these proteins are involved in protein-protein interactions while in the DNA bound state.
Hayes
C S
CS
Department of Biochemistry, University of Connecticut Health Center, Farmington, Connecticut 06030, USA.
Setlow
P
P
D000595:Amino Acid Sequence; D001407:Bacillus / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid; D003432:Cross-Linking Reagents; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D005022:Ethyldimethylaminopropyl Carbodiimide; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D012808:Sigma Factor; D014157:Transcription Factors
D001426:Bacterial Proteins; D003432:Cross-Linking Reagents; D017931:DNA Primers; D004268:DNA-Binding Proteins; D012808:Sigma Factor; D014157:Transcription Factors; C092468:spoIIR protein, Bacillus subtilis; C030069:spore-specific proteins, Bacillus; D005022:Ethyldimethylaminopropyl Carbodiimide