TCDB is operated by the Saier Lab Bioinformatics Group

2.A.42 The Hydroxy/Aromatic Amino Acid Permease (HAAAP) Family

The HAAAP family includes three well-characterized aromatic amino acid:H+ symport permeases of E. coli: a high affinity tryptophan-specific permease, Mtr, a low affinity tryptophan permease, TnaB, and a tyrosine-specific permease, TyrP, as well as two well-characterized hydroxy amino acid permeases, the serine permease, SdaC, of E. coli, and the threonine permease, TdcC, of E. coli. These proteins possess 403-443 amino acyl residues and exhibit eleven putative or established transmembrane α-helical spanners (TMSs). They all function in amino acid uptake. Homologues are present in a large number of Gram-negative and Gram-positive bacteria. These proteins exhibit topological features common to the eukaryotic amino acid/auxin permease (AAAP) family (TC #2.A.18), and they exhibit limited sequence similarity with some of them. Since members of the HAAAP family exhibit limited sequence similarity with the large APC family (TC #2.A.3), all of these proteins may be related.

SdaC of E. coli (TC #2.A.42.2.1) is also called DcrA, and together with a periplasmic protein DcrB (P37620), it has been reported to play a role in phage DNA uptake in conjunction with an outer membrane receptor of the OMR family (TC #1.B.14). Thus, FhuA (TC #1.B.14.1.4) transports phage T5 DNA while BtuB (TC #1.B.14.3.1) transports phage C1 DNA (Samsonov et al., 2002). DcuB is a putative lipoprotein found only in enteric bacteria.

The generalized transport reaction catalyzed by proteins of the HAAAP family is:

Amino acid (out) + nH+ (out) → Amino acid (in) + nH+ (in).

This family belongs to the: APC Superfamily.

References associated with 2.A.42 family:

Goss, T.J., H.P. Schweizer, and P. Datta. (1988). Molecular characterization of the tdc operon of Escherichia coli K-12. J. Bacteriol. 170: 5352-5359. 3053659
Katayama, T., H. Suzuki, T. Koyanagi, and H. Kumagai. (2002). Functional analysis of the Erwinia herbicola tutB gene and its product. J. Bacteriol. 184: 3135-3141. 12003958
Samsonov, V.V., V.V. Samsonov, and S.P. Sineoky. (2002). DcrA and dcrB Escherichia coli genes can control DNA injection by phages specific for BtuB and FhyA receptors. Res. Microbiol. 153: 639-646. 12558182
Sarsero, J.P. and A.J. Pittard. (1995). Membrane topology analysis of Escherichia coli K-12 Mtr permease by alkaline phosphatase and β-galactosidase fusions. J. Bacteriol. 177: 297-306. 7814318
Sarsero, J.P., P.J. Wookey, P. Gollnick, C. Yanofsky, and A.J. Pittard. (1991). A new family of integral membrane proteins involved in transport of aromatic amino acids in Escherichia coli. J. Bacteriol. 173: 3231-3234. 2022620
Shao, Z-Q, R.T. Lin, and E.B. Newman. (1994). Sequencing and characterization of the sdaCgene and identification of the sdaCBoperon in Escherichia coli K-12. Eur. J. Biochem. 222: 901-907. 8026499
Wookey, P.J. and A.J. Pittard. (1988). DNA sequence of the gene (tyrP) encoding the tyrosine-specific transport system of Escherichia coli. J. Bacteriol. 170: 4946-4949. 3049553
Zhao, Z., J.Y. Ding, W.H. Ma, N.Y. Zhou, and S.J. Liu. (2012). Identification and characterization of γ-aminobutyric acid uptake system GabPCg (NCgl0464) in Corynebacterium glutamicum. Appl. Environ. Microbiol. 78: 2596-2601. 22307305