PssA is required for alpha-amylase secretion in Antarctic Pseudoalteromonas haloplanktis.
Extracellular protein secretion is an essential feature in bacterial physiology. The ability to efficiently secrete diverse hydrolytic enzymes represents a key nutritional strategy for all bacteria, including micro-organisms living in extreme and hostile habitats, such as cold environments. However, little is known about protein secretion mechanisms in psychrophilic bacteria. In this study, the recombinant secretion of a cold-adapted alpha-amylase in the Antarctic Gram-negative Pseudoalteromonas haloplanktis TAC125 was investigated. By a combination of several molecular techniques, the function of the pssA gene was related to alpha-amylase secretion in this psychrophilic bacterium. Deletion of the pssA gene completely abolished amylase secretion without affecting the extracellular targeting of other substrates mediated by canonical secretion systems. The pssA gene product, PssA, is a multidomain lipoprotein, predicted to be localized in the bacterial outer membrane, and displaying three TPR (tetratricopeptide repeat) domains and two LysM modules. Based on functional annotation of these domains, combined with the experimental results reported herein, we suggest a role for PssA as a molecular adaptor, in charge of recruiting other cellular components required for specific alpha-amylase secretion. To the best of our knowledge, no proteins exhibiting the same domain organization have previously been linked to protein secretion.
Facoltà di Scienze Biotecnologiche Università di Napoli Federico II - Complesso Universitario M.S. Angelo via Cinthia 4, 80126 Napoli, Italy.|Dipartimento di Chimica Organica e Biochimica, Università di Napoli Federico II - Complesso Universitario M.S. Angelo via Cinthia 4, 80126 Napoli, Italy.
Ermenegilda
E
Parrilli
Dipartimento di Chimica Organica e Biochimica, Università di Napoli Federico II - Complesso Universitario M.S. Angelo via Cinthia 4, 80126 Napoli, Italy.
Maria
M
Giuliani
Dipartimento di Chimica Organica e Biochimica, Università di Napoli Federico II - Complesso Universitario M.S. Angelo via Cinthia 4, 80126 Napoli, Italy.
Cinzia
C
Pezzella
Génétique des Génomes Bactériens URA 2171 CNRS, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France.
Antoine
A
Danchin
Facoltà di Scienze Biotecnologiche Università di Napoli Federico II - Complesso Universitario M.S. Angelo via Cinthia 4, 80126 Napoli, Italy.|Dipartimento di Chimica Organica e Biochimica, Università di Napoli Federico II - Complesso Universitario M.S. Angelo via Cinthia 4, 80126 Napoli, Italy.
Gennaro
G
Marino
Facoltà di Scienze Biotecnologiche Università di Napoli Federico II - Complesso Universitario M.S. Angelo via Cinthia 4, 80126 Napoli, Italy.|Dipartimento di Chimica Organica e Biochimica, Università di Napoli Federico II - Complesso Universitario M.S. Angelo via Cinthia 4, 80126 Napoli, Italy.
Maria Luisa
ML
Tutino
D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D003080:Cold Temperature; D003360:Cosmids; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism*; D031161:Pseudoalteromonas / Q000201:enzymology* / Q000235:genetics; D000516:alpha-Amylases / Q000378:metabolism*
D001425:Bacterial Outer Membrane Proteins; D016695:Glycosyltransferases; D000516:alpha-Amylases