Crystal structure of Bacillus subtilis signal peptide peptidase A.

Signal peptide peptidase A (SppA) is a membrane-bound self-compartmentalized serine protease that functions to cleave the remnant signal peptides left behind after protein secretion and cleavage by signal peptidases. SppA is found in plants, archaea and bacteria. Here, we report the first crystal structure of a Gram-positive bacterial SppA.

Escherichia coli signal peptide peptidase A is a serine-lysine protease with a lysine recruited to the nonconserved amino-terminal domain in the S49 protease family.

Escherichia coli signal peptide peptidase A (SppA) is a serine protease which cleaves signal peptides after they have been proteolytically removed from exported proteins by signal peptidase processing. We present here results of site-directed mutagenesis studies of all the conserved serines of SppA in the carboxyl-terminal domain showing that only Ser 409 is essential for enzymatic activity. Also, we show that the serine hydrolase inhibitor FP-biotin inhibits SppA and modifies the protein but does not label the S409A mutant with an alanine substituted for the essential serine.

Crystal structure of a bacterial signal Peptide peptidase.

Signal peptide peptidase (Spp) is the enzyme responsible for cleaving the remnant signal peptides left behind in the membrane following Sec-dependent protein secretion. Spp activity appears to be present in all cell types, eukaryotic, prokaryotic and archaeal. Here we report the first structure of a signal peptide peptidase, that of the Escherichia coli SppA (SppA(EC)).

The FA2 gene of Chlamydomonas encodes a NIMA family kinase with roles in cell cycle progression and microtubule severing during deflagellation.

The NIMA kinases are one of several families of kinases that participate in driving the eukaryotic cell cycle. NIMA-related kinases have been implicated in G2/M progression, chromatin condensation and regulation of the centrosome cycle. Here we report the identification of a new member of this family, FA2, from Chlamydomonas reinhardtii.