Please use this identifier to cite or link to this item: https://doi.org/10.1016/j.jmb.2008.02.041
DC FieldValue
dc.titleCrystal Structure of the Polyextremophilic α-Amylase AmyB from Halothermothrix orenii: Details of a Productive Enzyme-Substrate Complex and an N Domain with a Role in Binding Raw Starch
dc.contributor.authorTan, T.-C.
dc.contributor.authorMijts, B.N.
dc.contributor.authorSwaminathan, K.
dc.contributor.authorPatel, B.K.C.
dc.contributor.authorDivne, C.
dc.date.accessioned2014-10-27T08:25:03Z
dc.date.available2014-10-27T08:25:03Z
dc.date.issued2008-05-09
dc.identifier.citationTan, T.-C., Mijts, B.N., Swaminathan, K., Patel, B.K.C., Divne, C. (2008-05-09). Crystal Structure of the Polyextremophilic α-Amylase AmyB from Halothermothrix orenii: Details of a Productive Enzyme-Substrate Complex and an N Domain with a Role in Binding Raw Starch. Journal of Molecular Biology 378 (4) : 850-868. ScholarBank@NUS Repository. https://doi.org/10.1016/j.jmb.2008.02.041
dc.identifier.issn00222836
dc.identifier.urihttp://scholarbank.nus.edu.sg/handle/10635/100369
dc.description.abstractThe gene for a membrane-bound, halophilic, and thermostable α-amylase, AmyB, from Halothermothrix orenii was cloned and sequenced. The crystal structure shows that, in addition to the typical domain organization of family 13 glycoside hydrolases, AmyB carries an additional N-terminal domain (N domain) that forms a large groove-the N-C groove-some 30 Å away from the active site. The structure of AmyB with the inhibitor acarbose at 1.35 Å resolution shows that a nonasaccharide has been synthesized through successive transglycosylation reactions of acarbose. Unexpectedly, in a complex of wild-type AmyB with α-cyclodextrin and maltoheptaose at 2.2 Å resolution, a maltotetraose molecule is bound in subsites - 1 to + 3, spanning the cleavage point at - 1/+ 1, with the - 1 glucosyl residue present as a 2So skew boat. This wild-type AmyB complex was obtained in the presence of a large excess of substrate, a condition under which it is possible to capture Michaelis complexes, which may explain the observed binding across - 1/+ 1 and ring distortion. We observe three methionine side chains that serve as "binding platforms" for glucosyl rings in AmyB, a seemingly rare occurrence in carbohydrate-binding proteins. The structures and results from the biochemical characterization of AmyB and AmyB lacking the N domain show that the N domain increases binding of the enzyme to raw starch. Furthermore, theoretical modeling suggests that the N-C groove can accommodate, spatially and chemically, large substrates such as A-starch. © 2008 Elsevier Ltd. All rights reserved.
dc.description.urihttp://libproxy1.nus.edu.sg/login?url=http://dx.doi.org/10.1016/j.jmb.2008.02.041
dc.sourceScopus
dc.subjectα-amylase
dc.subjectenzyme-substrate complex
dc.subjectmethionine interaction
dc.subjectN domain
dc.subjectpolyextremophilic
dc.typeArticle
dc.contributor.departmentBIOLOGICAL SCIENCES
dc.description.doi10.1016/j.jmb.2008.02.041
dc.description.sourcetitleJournal of Molecular Biology
dc.description.volume378
dc.description.issue4
dc.description.page850-868
dc.description.codenJMOBA
dc.identifier.isiut000256180100008
Appears in Collections:Staff Publications

Show simple item record
Files in This Item:
There are no files associated with this item.

SCOPUSTM   
Citations

53
checked on Sep 12, 2019

WEB OF SCIENCETM
Citations

44
checked on Sep 12, 2019

Page view(s)

63
checked on Sep 7, 2019

Google ScholarTM

Check

Altmetric


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.