Table 1. Strains and plasmids.

Strain or plasmid	Description	Source or reference
Strains
B. mallei
ATCC 23344	Wild-type strain; Polymyxin B resistant, zeocin and kanamycin sensitive	[42]
bpaB KO	Isogenic bpaB mutant strain of ATCC 23344; resistant to Polymyxin B and zeocin, kanamycin sensitive	This study
E. coli
EPI300	Cloning strain	epicenter Illumina
S17	Strain used for conjugational transfer of plasmids pBHR1ΔDra, pBpaB and pKASbpaB.zeo to B. mallei; sensitive to Polymyxin B	[43]
TUNER	Production strain used for purification of His- and GST-tagged BpaB proteins	EMD Millipore
Plasmids
pBHR1	Broad host range cloning vector; contains chloramphenicol and kanamycin resistance markers	MoBiTec Molecular Biotechnology
pBHR1ΔDra	pBHR1 containing a 339-nt deletion in the chloramphenicol resistance marker; confers resistance only to kanamycin	This study
pBpaB	pBHR1ΔDra containing the B. mallei ATCC 23344 bpaB gene; kanamycin resistant	This study
pCC1	Cloning vector; contains chloramphenicol resistance marker	epicenter Illumina
pCCbpaB	pCC1 containing the B. mallei ATCC 23344 bpaB gene; chloramphenicol resistant	This study
pCCbpaB.zeo	pCCbpaB in which a 1.4-kb fragment internal to the bpaB ORF is replaced with a 0.4-kb zeocin resistance cassette; confers resistance to chloramphenicol and zeocin	This study
pKAS46	Mobilizable suicide plasmid; contains kanamycin resistance marker	[44]
pKASbpaB.zeo	pKAS46 containing the insert from pCCbpaB.zeo; confers resistance to kanamycin and zeocin	This study
pEM7/ZEO	Source of the zeocin resistance marker	Life Technologies
pETcoco-1	Protein production vector; chloramphenicol resistant	EMD Millipore
pHisBpaB	pETcoco-1 producing BpaB residues 57–984 joined to an N-terminal His-tag; chloramphenicol resistant	This study
pGEX4T-2	Protein production vector; ampicillin resistant	GE Healthcare Life Sciences
pGSTBpaB	pGEX4T-2 producing BpaB residues 57–984 joined to an N-terminal GST-tag; ampicillin resistant	This study