Synthesis and characterization of a 29-amino acid residue DNA-binding peptide derived from alpha/beta-type small, acid-soluble spore proteins (SASP) of bacteria.
A 29-amino acid residue peptide (SASP-peptide) derived from the sequence of the putative DNA-contacting portion at the carboxyl terminus of an alpha/beta-type small, acid-soluble spore protein (SASP) of Bacillus subtilis has been synthesized by automated solid-phase methods and tested for its ability to interact with DNA. Circular dichroism (CD) spectroscopy reveals an interaction between this SASP-peptide and DNA, both by an increase in alpha-helix content of the peptide (which alone has a mostly random conformation) and by enhancement of the 275-nm CD band of the DNA. In contrast to results with intact alpha/beta-type SASP, however, the peptide does not induce a B----A conformational transition in the DNA. The SASP-peptide also binds to poly(dG).poly(dC) and protects this polynucleotide against DNase I digestion and UV light-induced cytosine dimer formation, parallel to findings made previously with native alpha/beta-type SASP. The results confirm the hypothesis that the carboxyl-terminal region of the alpha/beta-type SASP directly contacts DNA and possesses some, but not all, of the functional characteristics of the intact molecule.
Rao
H
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Department of Chemistry, Boston University, MA 02215.
Mohr
S C
SC
Fairhead
H
H
Setlow
P
P
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000737:chemistry* / Q000235:genetics; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D002942:Circular Dichroism; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000378:metabolism; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D010777:Photochemistry; D011089:Polydeoxyribonucleotides / Q000737:chemistry / Q000378:metabolism; D012808:Sigma Factor; D013055:Spectrophotometry, Infrared; D013171:Spores, Bacterial / Q000737:chemistry* / Q000235:genetics; D014157:Transcription Factors
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D010446:Peptide Fragments; D011089:Polydeoxyribonucleotides; D012808:Sigma Factor; D014157:Transcription Factors; C092468:spoIIR protein, Bacillus subtilis; C030069:spore-specific proteins, Bacillus; D003851:Deoxyribonucleases