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A novel TctA citrate transporter from an activated sludge metagenome: Structural and mechanistic predictions for the TTT family
Author(s) -
BatistaGarcía Ramón Alberto,
SánchezReyes Ayixon,
MillánPacheco César,
GonzálezZuñiga Víctor Manuel,
Juárez Soledad,
FolchMallol Jorge Luis,
Pastor Nina
Publication year - 2014
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.24529
Subject(s) - transporter , comamonas testosteroni , computational biology , context (archaeology) , solute carrier family , biology , genetics , biochemistry , chemistry , gene , paleontology
We isolated a putative citrate transporter of the tripartite tricarboxylate transporter (TTT) class from a metagenomic library of activated sludge from a sewage treatment plant. The transporter, dubbed TctA_ar, shares ∼50% sequence identity with TctA of Comamonas testosteroni (TctA_ct) and other β‐ Proteobacteria , and contains two 20‐amino acid repeat signature sequences, considered a hallmark of this particular transporter class. The structures for both TctA_ar and TctA_ct were modeled with I‐TASSER and two possible structures for this transporter family were proposed. Docking assays with citrate resulted in the corresponding sets of proposed critical residues for function. These models suggest functions for the 20‐amino acid repeats in the context of the two different architectures. This constitutes the first attempt at structure modeling of the TTT family, to the best of our knowledge, and could aid functional understanding of this little‐studied family. Proteins 2014; 82:1756–1764. © 2014 Wiley Periodicals, Inc.