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Eur J Biochem

Title:		"Biochemical, immunological and ultrastructural characterization of aggregation substances encoded by Enterococcus faecalis sex-pheromone plasmids"
Author(s):		Hirt H; Wanner G; Galli D; Wirth R;
Address:		"Lehrstuhl fur Mikrobiologie, Universitat Munchen, Federal Republic of Germany"
Journal Title:		Eur J Biochem
Year:		1993
Volume:		211
Issue:		3
Page Number:		711 - 716
DOI:		10.1111/j.1432-1033.1993.tb17600.x
ISSN/ISBN:		0014-2956 (Print) 0014-2956 (Linking)
Abstract:		"The sex-pheromone system of Enterococcus faecalis can be viewed as a unique and highly efficient plasmid-collection mechanism. The contact needed for transfer of the conjugative sex-pheromone plasmids is mediated by an adhesin, called aggregation substance, which is encoded by these plasmids. We show here that for 17 of the 18 sex-pheromone plasmids (pAM373 being the exception) described to date, their adhesins are immunologically related to each other. In each case, we observed the presence of an N-terminal fragment of about 78 kDa in addition to the 137-kDa form of mature aggregation substance. The cross-reactions were different for the various plasmids. In the case of pPD1 the 78-kDa fragment reacted only weakly. The aggregation substance encoded by sex-pheromone plasmid pAD1 (Asa1) was characterized in detail. The conditions used for SDS/PAGE had a drastic influence on the migration behavior of mature aggregation substance and differently migrating, interconvertible forms were identified. Preliminary data indicate that Asa1 might be a glycoprotein. Antibodies were isolated which are directed against the N- and C-terminal parts of aggregation substance. They showed about the same reactivity on Western blots; however, only antibodies directed against the N-terminal part of the aggregation substance could inhibit the bacterial cell/cell contact. The reactions of the two antibody preparations with induced cells of E. faecalis was analyzed by transmission electron microscopy. The results indicated that especially the N-terminal part of aggregation substance is exposed on the cell surface of E. faecalis; the C-terminal part seems to be much less exposed"
Keywords:		"Antibodies Antigens/immunology Bacterial Proteins/*chemistry/genetics/immunology Blotting, Western Electrophoresis, Polyacrylamide Gel Enterococcus faecalis/*chemistry/genetics Microscopy, Electron Peptide Fragments/chemistry/immunology *Plasmids Sex Attr;"
Notes:		"MedlineHirt, H Wanner, G Galli, D Wirth, R eng Research Support, Non-U.S. Gov't England 1993/02/01 Eur J Biochem. 1993 Feb 1; 211(3):711-6. doi: 10.1111/j.1432-1033.1993.tb17600.x"