Crystal structure of the sugar binding domain of the archaeal transcriptional regulator TrmB.
TrmB is an alpha-glucoside-sensing transcriptional regulator controlling two operons encoding maltose/trehalose and maltodextrin ABC transporters of Pyrococcus furiosus. The crystal structure of an N-terminal truncated derivative of TrmB (amino acids 2-109 deleted; TrmB(delta2-109)) was solved at 1.5 A 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(delta2-109) bound maltose, glucose, sucrose, and maltotriose, exhibiting Kd values of 6.8, 25, 34, and 160 microM, respectively. TrmB(delta2-109) 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: Ser229, Asn305, Gly320, Met321, Val324, Ile325, and Glu326. Six of these residues interact with the nonreducing glucosyl residue of maltose. The nonreducing glucosyl residue is shared by all substrates bound to TrmB, suggesting it as a common recognition motif.
Krug
Michael
M
Department of Biology, University of Konstanz, 78457 Konstanz, Germany.
Lee
Sung-Jae
SJ
Diederichs
Kay
K
Boos
Winfried
W
Welte
Wolfram
W
D020816:Amino Acid Motifs; D000596:Amino Acids / Q000737:chemistry; D019843:Archaeal Proteins / Q000737:chemistry*; D001665:Binding Sites; D002241:Carbohydrates / Q000737:chemistry; D002845:Chromatography; D018360:Crystallography, X-Ray; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000737:chemistry; D007700:Kinetics; D008320:Maltose / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D016133:Polymerase Chain Reaction; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D020027:Pyrococcus furiosus / Q000378:metabolism; D013395:Sucrose / Q000737:chemistry; D019712:Thermococcus / Q000378:metabolism*; D013997:Time Factors; D014157:Transcription Factors / Q000737:chemistry*; D014158:Transcription, Genetic; D014312:Trisaccharides / Q000737:chemistry
D000596:Amino Acids; D019843:Archaeal Proteins; D002241:Carbohydrates; D014157:Transcription Factors; D014312:Trisaccharides; D013395:Sucrose; C008317:maltotriose; D008320:Maltose; D005947:Glucose