Table 1. Location of substitution(s) in nifA.

Plasmid	Location of residues (substitutions) in NifA*
First screening:
pMNA-2-1	M173I (ATG→ATT), I196F, I217I, L418L, T516M
pMNA-5-1	No mutation
pMNA-11-1 and 19-1	M173V (ATG→GTG), D126Y, K208R, E413E
pMNA-12-1	M173V (ATG→GTG), V48G, T64S, R156H, P282T, E324A, R438H, G524D
pMNA-14-5 and 23-4	L41I, V96I, V132M, S241P, A360A, A376V, V473A
pMNA-24-1	M173I (ATG→ATA), P116L, A482V, M428L
pMNA-26-4	D126D, P146P
Second screening:
pMNA-2-2	V96A, S183R
pMNA-3-2	M173V (ATG→GTG), S16P, A376A
pMNA-4-1 and 7-1	M173I (ATG→ATT), A200A, R481F
pMNA-8-6	M173I (ATG→ATC), Y380Y
pMNA-9-2	M173I (ATG→ATT), V75A, K275K
pMNA-10-1	S32T, L486P
pMNA-12-2	E321N, F329F
pMNA-14-4 and 26-3	M173V (ATG→GTG), S22S, A243T, P511T
pMNA-15-4 and 16-4	M173I (ATG→ATA)
pMNA-17-5	M173I (ATG→ATA), T370A
pMNA-18-2	M173V (ATG→GTG), G126N, P207L
pMNA-20-3	M173I (ATG→ATT), Y522C
pMNA-24-2	M173V (ATG→GTG)
pMNA-27-1	M173I (ATG→ATT), K591N
pMNA-28-1	M173I (ATG→ATT), V86A
pMNA-30-1	M173I (ATGAATC), Y380Y, G556V

^*The substitutions and codon changes at the M173 residue are shown in bold type. Base substitutions that did not change the encoded amino acid are also indicated (e.g. I217I).