Interactions between flagellar and type III secretion proteins in Chlamydia pneumoniae

BMC Microbiology

Table 1 Interaction between the flagellar proteins of C. pneumoniae using the Bacterial-2-hybrid System

Plasmids	β-Galactosidase Activity in units/mg bacteria	Protein Functions
Negative Control
pT18 + pT25	412.0 ± 82.4	pT18: Empty vector
Positive Control:		pT25: Empty vector
pT18-PknD + pT25-CdsD-FHA-2	996.3 ± 50.0	FliI: Putative flagellar ATPase
Negative Interactions:		FliF: Putative flagellar MS ring protein
pT18-FliI + pT25-FliF	396.4 ± 32.1	FlhA: Putative flagellar integral membrane
pT18-FliF + pT25-Cpn0859	421.1 ± 25.9	protein
pT18-FliI + pT25-Cpn0706	404.4 ± 19.5	Cpn0859: Hypothetical C. pneumoniae
pT18-Cpn0706 + pT25-FlhA	443.0 ± 32.3	protein
Positive Interactions:		Cpn0706: Putative T3S chaperone
pT18-FliF + pT25-FlhA	847.2 ± 21.2	CdsL: Putative T3S ATPase tethering
pT18-FliI + pT25-FlhA	942.9 ± 123.1	protein
pT18-FliI + pT25-CdsL	874.3 ± 59.3	CopN: Putative T3S plug protein
pT18-FliI + pT25-CopN	943.2 ± 74.2	Cpn0322: Putative CdsU ortholog
pT18-Cpn0322 + pT25-FlhA	779.9 ± 32.7
pT18-CdsL + pT25-FlhA	832.1 ± 23.3

* FliI, FliF, FlhA, CdsL, CopN, Cpn0706 and Cpn0322 were cloned into both the pT18 and pT25 vectors. The bacterial-2-hybrid was performed in triplicate as described in the Materials and Methods section. Empty pT18 and pT25 vectors were used as a negative control while pT18-PknD + pT25-CdsD-FHA-2 was used as a positive control. The cut off for a positive interaction (577 units of activity/mg protein), is the mean of the negative control values (empty pT18 + pT25) plus two standard deviations obtained from 20 assays.

ISSN: 1471-2180