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Assembly of the secretion pores GspD , W za and CsgG into bacterial outer membranes does not require the O mp85 proteins BamA or TamA
Author(s) -
Dunstan Rhys A.,
Hay Iain D.,
Wilksch Jonathan J.,
Schittenhelm Ralf B.,
Purcell Anthony W.,
Clark Joan,
Costin Adam,
Ramm Georg,
Strugnell Richard A.,
Lithgow Trevor
Publication year - 2015
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.13055
Subject(s) - periplasmic space , bacterial outer membrane , bama , secretion , biology , microbiology and biotechnology , transmembrane protein , barrel (horology) , bacteria , membrane protein , inner membrane , membrane , biochemistry , escherichia coli , receptor , gene , materials science , genetics , composite material
Summary In G ram‐negative bacteria, β‐barrel proteins are integrated into the outer membrane by the β‐barrel assembly machinery, with key components of the machinery being the O mp85 family members BamA and TamA . Recent crystal structures and cryo‐electron microscopy show a diverse set of secretion pores in G ram‐negative bacteria, with α‐helix ( W za and GspD ) or β‐strand ( CsgG ) transmembrane segments in the outer membrane. We developed assays to measure the assembly of three distinct secretion pores that mediate protein ( GspD ), curli fibre ( CsgG ) and capsular polysaccharide ( W za) secretion by bacteria and show that depletion of BamA and TamA does not diminish the assembly of W za, GspD or CsgG . Like the well characterised pilotins for GspD and other secretins, small periplasmic proteins enhance the assembly of the CsgG β‐barrel. We discuss a model for integral protein assembly into the bacterial outer membrane, focusing on the commonalities and differences in the assembly of W za, GspD and CsgG .