1. SCHLOSSER, A, HAMANN, A., BOSSEMEYER, D., SCHNEIDER, E. AND BAKKER, E.P.
NAD+ binding to the Escherichia coli K+-uptake protein TrkA and sequence
similarity between TrkA and domains of a family of dehydrogenases suggest
a role for NAD+ in bacterial transport.
MOL.MICROBIOL. 9 533-543 (1993).
2. PARRA-LOPEZ, C., LIN, R., ASPEDON, A. AND GROISMAN, E.A.
A Salmonella protein that is required for resistance to antimicrobial
peptides and transport of potassium.
EMBO J. 13(17) 3964-3972 (1994).
3. MUNRO, A.W., RITCHIE, G.Y., LAMB, A.J., DOUGLAS, R.M. AND BOOTH, I.R.
The cloning and DNA-sequence of the gene for the glutathione-regulated
potassium-efflux system KefC of Escherichia coli.
MOL.MICROBIOL. 5 607-616 (1991).
The NAD(+)-binding protein TrkA is a component of a low-affinity K+
uptake system in E.coli . Sequence analysis reveals that the protein
consists of 2 tandemly arrayed halves that are 22% identical, a situation
that might have arisen through gene duplication. TrkA also exhibits
similarity to other E.coli proteins , in particular KefC, a glutathione-
regulated efflux protein , and to various dehydrogenase proteins that
possess NAD+ binding sites.
KUPTAKETRKA is a 5-element fingerprint that provides a signature for TrkA
and related proteins. The fingerprint was derived from an initial alignment
of 3 sequences: the motifs correspond to conserved regions spanning an
80-residue domain, which includes the predicted N-terminal NAD+/NADH
binding site (motif 1). Two iterations on OWL24.0 were required to reach
convergence, at which point a true set comprising 4 sequences was
identified. Two partial matches were also found (DHL2_LACCO and A49337),
both of which are dehydrogenases possessing NAD+/NADH binding sites.
An update on SPTR37_9f identified a true set of 6 sequences, and 7