Crystal Structure of the Sugar Binding Domain of the Archaeal Transcritional Regulator TrmB
نویسندگان
چکیده
TrmB is an -glucoside-sensing transcriptional regulator controlling two operons encoding maltose/trehalose and maltodextrin ABC transporters ofPyrococcus furiosus. The crystal structure of an N-terminal truncated derivative of TrmB (amino acids 2–109 deleted; TrmB 2–109) was solved at 1.5 Å resolution. This protein has lost its DNA binding domain but has retained its sugar recognition site. The structure represents a novel sugar-binding fold. TrmB 2–109 boundmaltose, glucose, sucrose, andmaltotriose, exhibitingKd values of 6.8, 25, 34, and 160 M, respectively. TrmB 2–109 behaved as a monomer in dilute buffer solution in contrast to the full-length protein, which is a dimer. Co-crystallization with bound maltose identified a binding site involving seven amino acid residues: Ser, Asn, Gly, Met, Val, Ile, and Glu. Six of these residues interact with the nonreducing glucosyl residue ofmaltose. The nonreducing glucosyl residue is shared by all substrates bound to TrmB, suggesting it as a common recognition motif.
منابع مشابه
The three-dimensional structure of TrmB, a transcriptional regulator of dual function in the hyperthermophilic archaeon Pyrococcus furiosus in complex with sucrose.
TrmB is a repressor that binds maltose, maltotriose, and sucrose, as well as other α-glucosides. It recognizes two different operator sequences controlling the TM (Trehalose/Maltose) and the MD (Maltodextrin) operon encoding the respective ABC transporters and sugar-degrading enzymes. Binding of maltose to TrmB abrogates repression of the TM operon but maintains the repression of the MD operon....
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