The Sip(Sli) gene of Streptomyces lividans TK24 specifies an unusual signal peptidase with a putative C-terminal transmembrane anchor.
Type I signal peptidases (SPases) are a widespread family of enzymes which remove signal peptides from proteins translocated across cellular membranes. Here, we report the first isolation of a gene coding for type I signal peptidase of Streptomyces, denoted Sip(Sli). The sip(sli) gene specifies a protein of 291 amino acids. Thus Sip(Sli) is much larger (approximately 100 amino acids) than other known SPases of Gram-positive bacteria and resembles SPases of Gram-negative bacteria, showing the highest degree of similarity to an SPase of the cyanobacterium Phormidium laminosum. Sip(Sli) contains conserved serine and lysine residues, which are believed to be required for the catalytic activity. Similar to other known SPases from Gram-positive bacteria, Sip(Sli) seems to have only one N-terminal transmembrane anchor. In addition, Sip(Sli) seems to contain a second transmembrane anchor at the C-terminus, which is an unusual feature for type I signal peptidases.
Schacht
S
S
Laboratory of Bacteriology, Rega Institute, Katholieke Universiteit Leuven, Belgium.
Van Mellaert
L
L
Lammertyn
E
E
Tjalsma
H
H
van Dijl
J M
JM
Bron
S
S
Anné
J
J
D000595:Amino Acid Sequence; D017931:DNA Primers; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D015723:Gene Library; D005798:Genes, Bacterial; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods; D015183:Restriction Mapping; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D012697:Serine Endopeptidases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D013302:Streptomyces / Q000201:enzymology / Q000235:genetics*
D017931:DNA Primers; D008565:Membrane Proteins; C052380:endodeoxyribonuclease NcoI; D015252:Deoxyribonucleases, Type II Site-Specific; D012697:Serine Endopeptidases; C026515:type I signal peptidase