Structural determinants of product specificity of sucrose isomerases.
The healthy sweetener isomaltulose is industrially produced from the conversion of sucrose by the sucrose isomerase SmuA from Protaminobacter rubrum. Crystal structures of SmuA in native and deoxynojirimycin complexed forms completed with modeling studies unravel the characteristics of the isomaltulose synthases catalytic pocket and their substrate binding mode. Comparison with the trehalulose synthase MutB highlights the role of Arg(298) and Arg(306) active site residues and surface charges in controlling product specificity of sucrose isomerases (isomaltulose versus trehalulose). The results provide a rationale for the specific design of optimized enzymes.
Institut de Biologie et Chimie des Protéines, UMR 5086-CNRS/Université de Lyon, IFR128 BioSciences Gerland-Lyon Sud, Lyon, France.
Stéphanie
S
Ravaud
Xavier
X
Robert
Hildegard
H
Watzlawick
Richard
R
Haser
Ralf
R
Mattes
Nushin
N
Aghajari
D017485:1-Deoxynojirimycin / Q000737:chemistry; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001120:Arginine / Q000737:chemistry; D020134:Catalytic Domain / Q000235:genetics; D018360:Crystallography, X-Ray; D020563:Gammaproteobacteria / Q000201:enzymology / Q000235:genetics; D005944:Glucosamine / Q000031:analogs & derivatives / Q000737:chemistry; D005964:Glucosyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019751:Intramolecular Transferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D007534:Isomaltose / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000302:isolation & purification; D046911:Macromolecular Substances; D008958:Models, Molecular; D011487:Protein Conformation; D055672:Static Electricity; D013379:Substrate Specificity; D013549:Sweetening Agents / Q000302:isolation & purification / Q000378:metabolism
D046911:Macromolecular Substances; D013549:Sweetening Agents; C501633:deoxynojirimycine; D017485:1-Deoxynojirimycin; D007534:Isomaltose; D001120:Arginine; D005964:Glucosyltransferases; C116853:sucrose isomerase; D019751:Intramolecular Transferases; C042002:isomaltulose synthase; D005944:Glucosamine; C008189:isomaltulose