Table 1.

Important mutations that disrupt BAM function. Summary of select mutants in Bam proteins that disrupted function and/or led to enhanced sensitivity to existing antibiotics (BamA (formerly called YaeT); BamB (formerly called YfgL); BamC (formerly called NlpB); BamD (formerly called YfiO); BamE (formerly called SmpA)).

	Bam Mutant	Mutation	Effect	Publication
1	BamA	BamAΔR64	Slight sensitivity to vancomycin and rifampin	Bennion et al., 2010. [36]
2	BamA	46 N-terminal insertions into POTRA domains and linker, 41 insertions into β-barrel	Variable vancomycin sensitivity	Browning et al., 2013. [37]
3	BamA	BamA G667V, T671A, R666C	Resistance to LlpA	Ghequire et al., 2018. [38]
4	BamA	BamA E470K	Resistance to MRL-494	Hart et al., 2019. [39]
5	BamA	BamA G429R, G429V, T434A, Q445P, A705T, G433D/E435K/F394V	Resistance to darobactin	Imai et al., 2019. [40]
6	BamA	G429V, G807V, E435K, Q445P, Q445P/T434A	Increased sensitivity to darobactin	Kaur et al., 2021 [41]
7	BamA	BamA F494L	With LptD Y721D, decreased vancomycin sensitivity; in WT, increased vancomycin sensitivity in nutrient-depleting conditions	Lee et al., 2018. [42]
8	BamA	R641E, Δ641RGF643, R641A/G642A/F643A, R641A/G642A, R641A/F643A, G642A/F643A	Increased sensitivity to vancomycin and rifampin	Leonard-Rivera et al., 2012. [43]
9	BamA	G807A, G807V, G807F	G807A, G807V, G807F: increased sensitivity to rifampicin; G807V, G807F: increased sensitivity to vancomycin	Lundquist et al., 2018. [44]
10	BamA	BamA D703Y	Decreased sensitivity to colistin	Luther et al., 2019. [45]
11	BamA	E554Q, H555Y, E554Q/H555Y, L6 deletion	E554Q, H555Y, E554Q/H555Y: decreased sensitivity to MAB1; L6 deletion: decreased sensitivity to MAB2	Storek et al., 2018. [46]
12	BamA	BamA G771A, F738, V660A/R661A, V660A/R661A-LL (loop-to-lumen disulfide bond)	A strain lacking BamA: G771A: hypersensitivity to rifampicin; Strain lacking DegP-BamA G771A, F738: resistant to rifampicin, V660A/R661A: sensitive to rifampicin; (BamA V660A/R661A)-LL: decreased sensitivity to rifampicin	Wzorek et al., 2017. [47]
13	BamA	BamA G429, G809, L501Q, P782, G429V/G807V	Resistance to dynobactin	Miller et al., 2022. [48]
14	BamB	ΔBamB, BamB D227A, D229A, L173S/L175S/R176A	ΔBamB: increased sensitivity to amoxicillin; ΔBamB, D277A, and L173S/L175S/R176A: increased sensitivity to vancomycin, erythromycin, and bacitracin; ΔBamB, D277A, D229A, and L173S/L175S/R176A: increased sensitivity to rifampin, flumequine, and enrofloxacin	Namdari et al., 2012. [49]
15	BamB	recessive LOF mutations in yfgML locus via independent element insertions	yfgML: resistance to bile salts, chlorobiphenyl vancomycin (CBPV)	Ruiz et al., 2005. [50]
16	BamB	ΔBamB	Increased sensitivity to VUF15259	Steenhuis et al., 2019. [51]
17	BamB	S172-A180 amino acid substitutions (scramble 1 & 2), L173S, L175S, R176A, L173S/L175S, L173S/R176A, L175S/R176A, L173S/L175S/R176A, YfgL(D227A)-His6	Scramble 1 and 2: vancomycin hypersensitivity; R176A and either L173S or L175S: vancomycin sensitivity; L173S & L175S & R176A: vancomycin hypersensitivity; YfgL(D227A)-His6: slight increase in vancomycin sensitivity	Vuong et al., 2008. [52]
18	BamE	omlA: 170 bp insertion mutation via single recombination	Increased sensitivity to novobiocin, coumermycinA1, chloramphenicol, SDS, and menadione	Fuangthong et al., 2008. [53]
19	BamE	C20G, I32G, Q34G/C, G35C, N36G/C, Y37G, L38G, I46G, V55G, L59G, M64G/C, D66G, F68G/C, W73G, F74G, Y75G/C, V76G, R78G, Q88C, L91G, L93G, F95G/C, L101G	Increased sensitivity to vancomycin	Knowles et al., 2011. [54]
20	BamE	mutant strains: 6B- producing lesser amounts of OmlA (BamE) protein, 3A- lacking a functional omlA gene	6B & 3A: increased sensitivity to SDS, deoxycholate 3A: increased sensitivity to nalidixic acid, rifampin, novobiocin, and chloramphenicol	Ochsner et al., 1999. [55]
21	BamE	smpA (strain lacking BamE)	Increased sensitivity (4-fold) to rifampin and cholate (2-fold); lethality on media with 0.5% SDS and 1 mM EDTA	Sklar et al., 2007. [56]
22	BamE	BamE deletion	Increased sensitivity to vancomycin	Volokhina et al., 2009. [57]
23	BamF	ΔBamF	Increased sensitivity to TritonX-100, SDS, nalidixic acid, rifampicin, vancomycin, and erythromycin	Anwari et al., 2012. [58]
24	BamA, BamB, BamC, BamE	ΔBamB, ΔBamC, ΔBamE, bamA101, BamA H555Y, V322A, P518L, T571M, G575D, G575S	ΔBamB, ΔBamC, ΔBamE, bamA101: increased sensitivity to MAB1; BamA H555Y, V322A, P518L, T571M, G575D, G575S: resistance to MAB1	Storek et al., 2019. [59]
25	BamA, BamB, BamD, BamE	mutant strain bamA101, ΔBamB, ΔBamC, BamD L13P	Mutant strain bamA101, BamD L13P: significantly increased sensitivity to batimastat; ΔBamB, ΔBamC: slightly increased sensitivity to batimastat	Konovalova et al., 2018. [60]
26	BamA, BamD	bamA101 (mutant strain with lower BamA expression), BamDRBS, BamDSS	Sensitivity to bile salts and SDS that is increased at temperatures lower than 37 °C	Mahoney et al., 2016. [61]
27	BamB, BamC	ΔyfgL (BamB deletion) ΔnlpB (BamC deletion)	ΔyfgL eliminated by kanamycin, increased sensitivity to SDS and novobiocin; ΔnlpB increased sensitivity to kanamycin	Onufryk et al., 2005. [62]
28	BamB, BamC, BamE	bamB::kan, ΔBamC/ΔBamE	bamB::kan, ΔBamC/ΔBamE: increased sensitivity to bacitracin, erythromycin, novobiocin, rifampin, and vancomycin	Rigel et al., 2012. [63]
29	BamC, BamD	BamC: insertion at codon 41 (nlpB::kan); BamD: insertion at codon 227 (yfiO::kan)	yfiO::kan allele caused lethality on a BamB LOF allele yfgl8 background; nlpB::dan yflG8 double mutants had irregular colony morphology when exposed to kanamycin	Wu et al., 2005. [15]