title: Structural and functional properties of the hsp16.4-bearing plasmid pER341 in Streptococcus thermophilus.
abstract: The plasmid pER341 (2798 bp) of Streptococcus thermophilus ST134 was sequenced and its open reading frame (ORF) regions were characterized. Analysis of nucleotide sequences showed the putative translation product of ORF1 (rep) sharing a high level of homology with replication proteins of several small plasmids present in lactic acid bacteria and staphylococci. This and homology of regions of plus-strand (ORI) and minus-strand (ssoA) origin of replication with pC194-class plasmids indicated that pER341 replicates by the rolling-circle mechanism. ORF2 corresponded to a putative hsp gene that apparently encodes Hsp16.4, a 142-amino-acid heat stress protein. Hsp16.4 shared significant identity with other small, 18-kDa-class heat stress proteins from prokaryotic and eukaryotic sources. Hsp16.4 is apparently the first plasmidborne low-molecular-weight heat stress protein reported in dairy fermentation bacteria with a potential role in temperature-regulated functions in S. thermophilus.
authors.affiliation: Agricultural Research Service, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, Pennsylvania, 19038, USA. gsomkuti@arserrc.gov
authors.forename: G A
authors.initials: GA
authors.lastname: Somkuti
authors.forename: D K
authors.initials: DK
authors.lastname: Solaiman
authors.forename: D H
authors.initials: DH
authors.lastname: Steinberg
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D004265:DNA Helicases / Q000235:genetics; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000235:genetics; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D010957:Plasmids / Q000737:chemistry* / Q000302:isolation & purification; D012333:RNA, Messenger / Q000032:analysis; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013291:Streptococcus / Q000235:genetics*; D013329:Structure-Activity Relationship; D015534:Trans-Activators / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C117076:HSP16.4 protein, bacteria; D006360:Heat-Shock Proteins; D012333:RNA, Messenger; D015534:Trans-Activators; C045264:replication initiator protein; D004265:DNA Helicases