The catalytic mechanism of endoplasmic reticulum signal peptidase appears to be distinct from most eubacterial signal peptidases.
Many type I signal peptidases from eubacterial cells appear to contain a serine/lysine catalytic dyad. In contrast, our data show that the signal peptidase complex from the endoplasmic reticulum lacks an apparent catalytic lysine. Instead, a serine, histidine, and two aspartic acids are important for signal peptidase activity by the Sec11p subunit of the yeast signal peptidase complex. Amino acids critical to the eubacterial signal peptidases and Sec11p are, however, positioned similarly along their primary sequences, suggesting the presence of a common structural element(s) near the catalytic sites of these enzymes.
VanValkenburgh
C
C
Department of Microbiology and Immunology, School of Medicine, Vanderbilt University, Nashville, Tennessee 37232-2363, USA.
Chen
X
X
Mullins
C
C
Fang
H
H
Green
N
N
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001419:Bacteria / Q000201:enzymology*; D001483:Base Sequence; D002384:Catalysis; D017931:DNA Primers; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010447:Peptide Hydrolases; D011485:Protein Binding; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D017931:DNA Primers; D005656:Fungal Proteins; D008565:Membrane Proteins; D029701:Saccharomyces cerevisiae Proteins; D010447:Peptide Hydrolases; C061149:SEC11 protein, S cerevisiae; D012697:Serine Endopeptidases; C106171:SPC3 protein, S cerevisiae; C026515:type I signal peptidase