Structure and Function of Human Xylulokinase, an Enzyme with Important Roles in Carbohydrate Metabolism

Show simple item record Bunker, RD Bulloch, EMM Dickson, JMJ Loomes, KM Baker, EN
dc.coverage.spatial United States 2022-06-13T23:06:52Z 2022-06-13T23:06:52Z 2013-01-18
dc.identifier.citation (2013). Journal of Biological Chemistry, 288(3), 1643-1652.
dc.identifier.issn 0021-9258
dc.description.abstract D-Xylulokinase (XK; EC catalyzes the ATP-dependent phosphorylation of D-xylulose (Xu) to produce xylulose 5-phosphate (Xu5P). In mammals, XK is the last enzyme in the glucuronate-xylulose pathway, active in the liver and kidneys, and is linked through its product Xu5P to the pentose-phosphate pathway. XK may play an important role in metabolic disease, given that Xu5P is a key regulator of glucose metabolism and lipogenesis. We have expressed the product of a putative human XK gene and identified it as the authentic human D-xylulokinase (hXK). NMR studies with a variety of sugars showed that hXK acts only on D-xylulose, and a coupled photometric assay established its key kinetic parameters as Km(Xu) = 24 ± 3 μM and kcat = 35 ± 5 s−1. Crystal structures were determined for hXK, on its own and in complexes with Xu, ADP, and a fluorinated inhibitor. These reveal that hXK has a two-domain fold characteristic of the sugar kinase/hsp70/actin superfamily, with glycerol kinase as its closest relative. Xu binds to domain-I and ADP to domain-II, but in this open form of hXK they are 10 Å apart, implying that a large scale conformational change is required for catalysis. Xu binds in its linear keto-form, sandwiched between a Trp side chain and polar side chains that provide exquisite hydrogen bonding recognition. The hXK structure provides a basis for the design of specific inhibitors with which to probe its roles in sugar metabolism and metabolic disease.
dc.format.medium Print-Electronic
dc.language eng
dc.publisher Elsevier BV
dc.relation.ispartofseries Journal of Biological Chemistry
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher.
dc.subject Humans
dc.subject Escherichia coli
dc.subject Phosphotransferases (Alcohol Group Acceptor)
dc.subject Xylulose
dc.subject Pentosephosphates
dc.subject Recombinant Proteins
dc.subject Adenosine Diphosphate
dc.subject Crystallography, X-Ray
dc.subject Magnetic Resonance Spectroscopy
dc.subject Gene Expression
dc.subject Catalytic Domain
dc.subject Protein Structure, Secondary
dc.subject Protein Structure, Tertiary
dc.subject Substrate Specificity
dc.subject Kinetics
dc.subject Hydrogen Bonding
dc.subject Models, Molecular
dc.subject Digestive Diseases
dc.subject Liver Disease
dc.subject 2.1 Biological and endogenous factors
dc.subject 1.1 Normal biological development and functioning
dc.subject Generic health relevance
dc.subject Science & Technology
dc.subject Life Sciences & Biomedicine
dc.subject Biochemistry & Molecular Biology
dc.subject DATA QUALITY
dc.subject GLUCOSE
dc.subject LIVER
dc.subject 0601 Biochemistry and Cell Biology
dc.subject Biomedical
dc.subject 03 Chemical Sciences
dc.subject 06 Biological Sciences
dc.subject 11 Medical and Health Sciences
dc.title Structure and Function of Human Xylulokinase, an Enzyme with Important Roles in Carbohydrate Metabolism
dc.type Journal Article
dc.identifier.doi 10.1074/jbc.M112.427997
pubs.issue 3
pubs.begin-page 1643
pubs.volume 288 2022-05-02T09:00:21Z
dc.rights.holder Copyright: The American Society for Biochemistry and Molecular Biology en
dc.identifier.pmid 23179721 (pubmed)
pubs.end-page 1652
pubs.publication-status Published
dc.rights.accessrights en
pubs.subtype Article
pubs.elements-id 365269 Science Biological Sciences Science Research Maurice Wilkins Centre (2010-2014)
dc.identifier.eissn 1083-351X
dc.identifier.pii S0021-9258(20)46578-0
pubs.record-created-at-source-date 2022-05-02 2012-11-23

Files in this item

Find Full text

This item appears in the following Collection(s)

Show simple item record


Search ResearchSpace