Association of novel domain in active site of archaic hyperthermophilic maltogenic amylase from Staphylothermus marinus.
Staphylothermus marinus maltogenic amylase (SMMA) is a novel extreme thermophile maltogenic amylase with an optimal temperature of 100 °C, which hydrolyzes α-(1-4)-glycosyl linkages in cyclodextrins and in linear malto-oligosaccharides. This enzyme has a long N-terminal extension that is conserved among archaic hyperthermophilic amylases but is not found in other hydrolyzing enzymes from the glycoside hydrolase 13 family. The SMMA crystal structure revealed that the N-terminal extension forms an N' domain that is similar to carbohydrate-binding module 48, with the strand-loop-strand region forming a part of the substrate binding pocket with several aromatic residues, including Phe-95, Phe-96, and Tyr-99. A structural comparison with conventional cyclodextrin-hydrolyzing enzymes revealed a striking resemblance between the SMMA N' domain position and the dimeric N domain position in bacterial enzymes. This result suggests that extremophilic archaea that live at high temperatures may have adopted a novel domain arrangement that combines all of the substrate binding components within a monomeric subunit. The SMMA structure provides a molecular basis for the functional properties that are unique to hyperthermophile maltogenic amylases from archaea and that distinguish SMMA from moderate thermophilic or mesophilic bacterial enzymes.
Department of Biological Sciences, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-701, Korea.
Tae-Yang
TY
Jung
Dan
D
Li
Jong-Tae
JT
Park
Se-Mi
SM
Yoon
Phuong Lan
PL
Tran
Byung-Ha
BH
Oh
Štefan
Š
Janeček
Sung Goo
SG
Park
Eui-Jeon
EJ
Woo
Kwan-Hwa
KH
Park
D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics; D001419:Bacteria / Q000201:enzymology / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D019620:Desulfurococcaceae / Q000201:enzymology* / Q000235:genetics; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000235:genetics; D006868:Hydrolysis; D009844:Oligosaccharides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship
D019843:Archaeal Proteins; D001426:Bacterial Proteins; D009844:Oligosaccharides; D006026:Glycoside Hydrolases; C120909:glucan 1,4-alpha-maltohydrolase