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dc.contributor.authorBustad, Helene J.
dc.contributor.authorVorland, Marta
dc.contributor.authorRønneseth, Eva
dc.contributor.authorSandberg, Sverre
dc.contributor.authorMartinez, Aurora
dc.contributor.authorToska, Karen
dc.identifier.citationBioscience Reports 2013, 33:617-U203eng
dc.description.abstractThe autosomal dominantly inherited disease AIP (acute intermittent porphyria) is caused by mutations in HMBS [hydroxymethylbilane synthase; also known as PBG (porphobilinogen) deaminase], the third enzyme in the haem biosynthesis pathway. Enzyme-intermediates with increasing number of PBG molecules are formed during the catalysis of HMBS. In this work, we studied the two uncharacterized mutants K132N and V215E comparative with wt (wild- type) HMBS and to the previously reported AIP-associated mutants R116W, R167W and R173W. These mainly present defects in conformational stability (R116W), enzyme kinetics (R167W) or both (R173W). A combination of native PAGE, CD, DSF (differential scanning fluorimetry) and ion-exchange chromatography was used to study conformational stability and activity of the recombinant enzymes. We also investigated the distribution of intermediates corresponding to specific elongation stages. It is well known that the thermostability of HMBS increases when the DPM (dipyrromethane) cofactor binds to the apoenzyme and the holoenzyme is formed. Interestingly, a decrease in thermal stability was measured concomitant to elongation of the pyrrole chain, indicating a loosening of the structure prior to product release. No conformational or kinetic defect was observed for the K132N mutant, whereas V215E presented lower conformational stability and probably a perturbed elongation process. This is in accordance with the high association of V215E with AIP. Our results contribute to interpret the molecular mechanisms for dysfunction of HMBS mutants and to establish genotype–phenotype relations for AIP.eng
dc.publisherPortland Press Publishingeng
dc.rightsAttribution CC BY 3.0eng
dc.subjectacute intermittent porphyria (AIP)eng
dc.subjectgenotype–phenotype relationshipseng
dc.subjectligand–protein interactioneng
dc.subjectporphobilinogen (PBG) deaminaseeng
dc.subjectthermal stabilityeng
dc.titleConformational stability and activity analysis of two hydroxymethylbilane synthase mutants, K132N and V215E, with different phenotypic association with acute intermittent porphyriaeng
dc.typeJournal articleeng
dc.subject.nsiVDP::Medisinske fag: 700::Basale medisinske, odontologiske og veterinærmedisinske fag: 710::Medisinsk biokjemi: 726
dc.subject.nsiVDP::Midical sciences: 700::Basic medical, dental and veterinary sciences: 710::Medical biochemistry: 726
dc.rights.holderCopyright 2013 The Author(s)eng
bora.peerreviewedPeer reviewedeng
dc.type.documentJournal article
noa.nsiVDP::Medisinske Fag: 700eng

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Attribution CC BY 3.0
Except where otherwise noted, this item's license is described as Attribution CC BY 3.0