>cd07019 S49_SppA_1 Signal peptide peptidase A (SppA), a serine protease, has catalytic Ser-Lys dyad. Signal peptide peptidase A (SppA; Peptidase S49; Protease IV): SppAs in this subfamily are found in all three domains of life and are involved in the cleavage of signal peptides after their removal from the precursor proteins by signal peptidases. Site-directed mutagenesis and sequence analysis have shown these bacterial, archaeal and thylakoid SppAs to be serine proteases. The predicted active site serine for members in this family occurs in a transmembrane domain. Mutagenesis studies also suggest that the catalytic center comprises a Ser-Lys dyad (both residues absolutely conserved within bacteria, chloroplast and mitochondrial signal peptidase family members) and not the usual Ser-His-Asp catalytic triad found in the majority of serine proteases. In addition to the carboxyl-terminal protease domain that is conserved in all the S49 family members, the E. coli SppA contains an amino-te

Probab=95.21  E-value=0.19  Score=29.29  Aligned_cols=24  Identities=25%  Similarity=0.187  Sum_probs=19.0

Q ss_pred             CCCHHHHHHHHHHHHHHHHHHHHC
Q ss_conf             988899885999999998999955
Q gi|254781049|r  178 ELQGQARIDGGDLFPNLYKAFCDK  201 (398)
Q Consensus       178 g~~~~~~~~~~~ii~~L~~~f~e~  201 (398)
T Consensus       142 ~lt~e~r~~~q~~vd~~~~~F~~~  165 (211)
T cd07019         142 ALPPEAQLGLQLSIENGYKRFITL  165 (211)
T ss_pred             CCCHHHHHHHHHHHHHHHHHHHHH
T ss_conf             999999999999999999999999