Table 1. Bacterial strains and plasmids used in this study.

	Genotype and/or phenotype	Reference of source
Strains
N16961	WT V. cholerae O1 El Tor strain; genomic sequence available: Smr	Lab strain
Plasmids
pET30(abc)	Expression vectors allowing cloning of fragments in each of three reading frames; Kanr	Novagen
pLHEAB1	pET30(a) with intact pilQ gene amplified by PCR from N16961 (1734 bp), and cloned in NdeI and XhoI sites in vector; Kanr	This work
pLHEAB2	pET30(a) with intact pilA gene amplified by PCR from N16961 (459 bp), and cloned in NdeI and XhoI sites in vector; Kanr	This work
pLHEAB3	pET30(a) with intact tcpA gene amplified by PCR from N16961 (672 bp), and cloned in NdeI and XhoI sites in vector; Kanr	This work
pLHMA1	pET30(a) with intact tcpF gene amplified by PCR from N16961 (1014 bp), and cloned in NdeI and XhoI sites in vector; Kanr	This work
pLH1	pET30(a) with intact mshA gene amplified by PCR from N16961 (534 bp), and cloned in EcoRV and XhoI sites in vector; Kanr	This work

Sm^r, streptomycin-resistant; Kan^r, kanamycin-resistant; Ap^r, ampicillin-resistant