Heterogeneity of S-layer proteins from aggregating and non-aggregating Lactobacillus kefir strains.

MOBILIP,; SERRADELL M. A.,; TREJO S,; AVILES PUIGVERT, X ;; ABRAHAM A.G.;; DE ANTONI G,L.

ANTON LEEUW INT. J. G.

Springer-

Lugar: The Netherland; Año: 2009 vol. 95 p. 363 - 372

0003-6072

Abstract Since the presence of S-layer protein conditioned the autoaggregation capacity of some strains of Lactobacillus kefir, S-layer proteins from aggregating and non-aggregating L. kefir strains were characterized by immunochemical reactivity, MALDI-TOF spectrometry and glycosylation analysis. Two anti-S-layer monoclonal antibodies (Mab5F8 and Mab1F8) were produced; in an indirect enzyme-linked immunosorbent assay (ELISA) Mab1F8 recognised S-layer proteins from all L. kefir tested while Mab5F8 recognised only S-layer proteins from aggregating strains. Periodic Acid-Schiff staining of proteins after polyacrylamide gel electrophoresis under denaturing conditions revealed that all L. kefir S-layer proteins tested were glycosylated. Growth of bacteria in the presence of the N-glycosylation inhibitor tunicamycin suggested the presence of glycosydic chains O-linked to the protein backbone. MALDI-TOF peptide map fingerprint for S-layer proteins from 12 L. kefir strains showed very similar patterns for the aggregating strains, different from those for the non-aggregating ones. No positive match with other protein spectra in MSDB Database was found. Our results revealed a high heterogeneity among S-layer proteins from different L. kefir strains but also suggested a correlation between the structure of these S-layer glycoproteins and the aggregation properties of whole bacterial cells.