Table 1. Strains, plasmids and constructs employed in the study.

Strain or plasmid	Relevant characteristics	Reference or source
N. meningitidis strains
MC58	Serogroup B, isolated in the UK, 1983	[72]
M1080	Serogroup B, isolated in the USA, 1969	[73]
MC58 ΔpilG	pilG K.O. clone of MC58, erythromycin resistant	Clone GG1 in [20]
MC58-pilG:aph	MC58 transformed with pSAF67, carrying wild type pilG with aph inserted downstream	This study
MC58-pilG-EEE:aph	MC58 transformed with pSAF68B, carrying pilG EEE39-41AAA with aph inserted downstream	This study
MC58-pilG-RKK:aph	MC58 transformed with pSAF69, carrying wild type pilG RKK43-45AAA with aph inserted downstream	This study
M1080-pilG:aph	M1080 transformed with pSAF67, carrying wild type pilG with aph inserted downstream	This study
M1080-pilG-EEE:aph	M1080 transformed with pSAF68B, carrying pilG EEE39-41AAA with aph inserted downstream	This study
M1080-pilG-RKK:aph	M1080 transformed with pSAF69, carrying wild type pilG RKK43-45AAA with aph inserted downstream	This study
E. coli strain
ER2566	Expression strain with a chromosomal copy of the T7 RNA polymerase gene	New England Biolabs
Plasmid/construct
pET28b(+)	Expression vector based on a T7 promoter-driven system, 6×His tag, Kanr	Novagen
pPilG1	pET28b(+) with PilGFL/1-410 insert	This study
pPilG-I	pET28b(+) with PilG1-256 insert	This study
pPilG-II	pET28b(+) with PilG1-178 insert	This study
pPilG-II:1	pET28b(+) with PilG1-60 insert	This study
pPilG-II:3	pET28b(+) with PilG1-140 insert	This study
pPilG-II:4–1	pET28b(+) with PilG1-80 insert	This study
pPilG-II:4–2	pET28b(+) with PilG1-81 insert	This study
pPilG-II:6–1	pET28b(+) with PilG30-80 insert	This study
pPilG-II:6–2	pET28b(+) with PilG30-81 insert	This study
pPilG-IV	pET28b(+) with PilG257-410 insert	This study
pPilG-V	pET28b(+) with PilG166-410 insert	This study
pPilG-K3A	pPilG1 with alanine substitution at aa 3	This study
pPilG-KK12-13AA	pPilG1 with alanine substitution at aa 12–13	This study
pPilG-E14A	pPilG1 with alanine substitution at aa 14	This study
pPilG-KR15-16AA	pPilG1 with alanine substitution at aa 15–16	This study
pPilG-EEE39-41AAA	pPilG1 with alanine substitution at aa 39–41	This study
pPilG-RKK43-45AAA	pPilG1 with alanine substitution at aa 43–45	This study
pPilG-E41H/RKK43-45AAA	pPilG1 with alanine substitution at aa 43–45 and change of aa 41 from E to H	This study
pPilG-Q55A	pPilG1 with alanine substitution at aa 55	This study
pPilG-SS62-63AA	pPilG1 with alanine substitution at aa 62–63	This study
pBluescript II SK(+)		Stratagene
pUP6	Tn5 aph containing plasmid	[6]
pOHA-D4	Variant of p0-DUS, containing AT-DUS	[34, 74]
pSAF67	pBluescript II SK(+) based plasmid containing wild type pilG, Kanr	This study
pSAF68B	pSAF67 derivative, pilG EEE39-41AAA, Kanr	This study
pSAF69	pSAF67 derivative, pilG RKK43-45AAA, Kanr	This study