Table 1. Strains and plasmids used in this study.

Bacterial strains:	Genotype/relevant characteristic	NhhA phenotype	Reference
PMC21	N. meningitidis, serogroup C	Expresses wild-type NhhAPMC21	This study
¢3	N.meningitidis, derived from MC58, acapsulate (ΔsiaD::erm), Opa - variant	Expresses wild-type levels NhhAMC58	[23]
2A	N.meningitidis, ¢3 derivative, nhhA::kan	NhhA expression abolished	[6]
¢3lgtA	¢3 derivative, lgtA::kan	Expresses wild-type levels of NhhAMC58	[18]
7G2	N.meningitidis, ¢3lgtA derivative LOS phenotype fixed L8	Expresses wild-type levels of NhhAMC58	This study
P6	7G2 derivative, porA replaced by nhhAPMC21	Over-expression of NhhAPMC21, wild-type levels of NhhAMC58	This study
P6ΔOpcA	P6 derivative. Δopc	Over-expression of NhhAPMC21, wild-type levels of NhhAMC58	This study
PΔ5	7G2 derivative, porA replaced by nhhABgl	Over-expression of NhhABgl, (Bgl II deletion) wild-type levels of NhhAMC58	This study
PΔ5ΔOpcA	PΔ5 derivative, Δopc	Over-expression of NhhABgl, (Bgl II deletion) wild-type levels of NhhAMC58	This study
PSO1	7G2 derivative, porA replaced by nhhASO1	Over-expression of NhhASO1, (splice-overlap deletion) wild-type levels of NhhAMC58	This study
PSO1.17A	PSO1 derivative, Δopc::tet	Over-expression of NhhASO1, (splice-overlap deletion) wild-type levels of NhhAMC58	This study
Plasmids
pC014K	porA gene with kanamycin resistance gene cloned downstream		[24]
pIP52(PMC21)	nhhAPMC21 cloned into pC014K		This study
pIP52(PMC21Bgl)	pIP52(PMC21) derivative: BglII deletion of nhhAPMC21		This study
pIPSO1	Splice overlap deletion of nhhAPMC21 cloned into pC014K		This study
pBE501	Plasmid contains opc gene		[16]
pIP14	opc deletion plasmid: HindIII/StyI digest of pBE501		This study
pOpcTet	pBE501 derivative, opc::tetM		This study
pT7lgtAG7			This study
pMJ1b11	Contains lgtABE locus		[18]