TABLE 3.

Mutations and amino acid changes that allow PurF-independent PRA synthesis

Strain	trp allele	Causative mutation	Amino acid change	Three-dimensional locationa
DM7863	trpC3620	G-A	A405T	Conserved active site residue in PR-AnI domainb
DM7865	trpC3621	G-A	G255D	Hinge region between PR-AnI and IGPS
DM7867	trpC3622	G-A	A358T	Nonconserved residue in PR-AnI domain
DM7868	trpC3623	G-A	G435D	Fully conserved active site residue in PR-AnI domain
DM7869	trpC3624	C-T	G339Ter (UAG)	Truncates half of the PR-AnI domain
DM7870	trpC3626	Insertion at bp 798	6-amino-acid insertion	Beginning of the first α-helix of PR-AnI domain

^aA 2.8-Å-resolution crystal structure of TrpC from Escherichia coli as solved by Priestle et al. (26).

^bConserved residues were determined by the amino acid sequence alignment of TrpC from several organisms (26).