Cloning and nucleotide sequence analysis of psaA, the Streptococcus pneumoniae gene encoding a 37-kilodalton protein homologous to previously reported Streptococcus sp. adhesins.
Gene psaA, which encodes the Streptococcus pneumoniae 37-kDa protein, was cloned in Escherichia coli, and its complete nucleotide sequence was determined. Analysis of the sequence of the 2.4-kb cloned fragment revealed three open reading frames (ORFs). ORF2, which is 933 bp long, was identified as psaA. The two other ORFs identified flank psaA. ORF1, located upstream of psaA, is 836 nucleotides long and encodes a protein with a calculated molecular mass of 29,843 Da. The sequence for ORF3, located downstream of psaA, was only partially determined. Northern (RNA) blot analysis of pneumococcal RNA suggests that psaA is transcribed as part of a polycistronic message. Analysis of the primary structure of the protein encoded by this gene indicated significant similarity to two previously reported streptococcal proteins, SsaB (80% similarity) and FimA (92.3% similarity), from S. sanguis and S. parasanguis, respectively. These two homologous proteins have been shown to be associated with bacterial adhesion, and the possibility of a similar role for PsaA is hypothesized.
Sampson
J S
JS
Division of Bacterial and Mycotic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333.
O'Connor
S P
SP
Stinson
A R
AR
Tharpe
J A
JA
Russell
H
H
D018829:Adhesins, Bacterial; D000595:Amino Acid Sequence; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D002352:Carrier Proteins; D003001:Cloning, Molecular; D015870:Gene Expression; D005798:Genes, Bacterial; D008074:Lipoproteins; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D012329:RNA, Bacterial / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013296:Streptococcus pneumoniae / Q000276:immunology*
D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D002352:Carrier Proteins; D008074:Lipoproteins; D026901:Membrane Transport Proteins; C085000:PsaA protein, Streptococcus; D012329:RNA, Bacterial; D012333:RNA, Messenger