The complete triphosphate moiety of non-hydrolyzable substrate analogues is required for a conformational shift of the flexible C-terminus in E. coli dUTP pyrophosphatase

Vertessy, Beata G. (author)

Larsson, Gunilla (author)

Persson, Tina (author)

Bergman, Anna-Carin (author)

Persson, Rebecca (author)

Nyman, Per-Olof (author): Lund University,Lunds universitet,Biokemi och Strukturbiologi,Centrum för Molekylär Proteinvetenskap,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Biochemistry and Structural Biology,Center for Molecular Protein Science,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH

(creator_code:org_t)

Related links:: http://dx.doi.org/10...; show more...; https://lup.lub.lu.s...; https://doi.org/10.1...; show less...

Abstract Subject headings

The molecular mechanism of substrate analogue interaction with Escherichia coli dUTPase was investigated, using the non-hydrolyzable 2'-deoxyuridine 5'-(α,β-imido)triphosphate (α,β-imido-dUTP). Binding of this analogue induces a difference in the far UV circular dichroism (CD) spectrum arguing for a significant change in protein conformation. The spectral shift is strictly Mg2+-dependent, does not appear with dUDP instead of α,β-imido-dUTP and is not elicited if the flexible C-terminal arm is deleted from the protein by limited tryptic digestion. Involvement of the C-terminal arm in α,β-imido-dUTP binding is consistent with the finding that this analogue protects against tryptic hydrolysis at Arg-141. Near UV CD of ligand-enzyme complexes reveals a characteristic difference in the microenvironments of enzyme-bound dUDP and α,β-imido-dUTP, a difference not observable in C-terminally truncated dUTPase. The results suggest that (i) closing of the active site during the catalytic cycle, through the movement of the C-terminal arm, requires the presence of the complete triphosphate moiety of the substrate in complex with Mg2+, and (ii) after catalytic cleavage the active site pops open to facilitate product release.

By the author/editor: Vertessy, Beata ...; Larsson, Gunilla; Persson, Tina; Bergman, Anna-Ca ...; Persson, Rebecca; Nyman, Per-Olof

About the subject

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.