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:

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.
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.
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.
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.
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.
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.
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.
 

Examples:

TC#NameOrganismal TypeExample
2.A.42.1.1Tyrosine permease Bacteria TyrP of E. coli
 
2.A.42.1.2Tryptophan-specific permease Bacteria Mtr of E. coli
 
2.A.42.1.3Low affinity tryptophan permease Bacteria TnaB of E. coli
 
2.A.42.1.4Tyrosine permease (most similar in sequence to Mtr of E. coli)BacteriaTutB of Erwinia herbicola
 
2.A.42.2.1Serine/threonine permease Bacteria SdaC of E. coli
 
2.A.42.2.2Threonine permease Bacteria TdcC of E. coli