当前位置： SCI文献检索 > ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS期刊下所有文献 > An arginine residue involved in allosteric regulation of cystathionine β-synthase (CBS) domain-containing pyrophosphatase.

An arginine residue involved in allosteric regulation of cystathionine β-synthase (CBS) domain-containing pyrophosphatase.

Abstract：

:Inorganic pyrophosphatase containing a pair of regulatory CBS domains (CBS-PPase1) is allosterically inhibited by AMP and ADP and activated by ATP and diadenosine polyphosphates. Mononucleotide binding to CBS domains and substrate binding to catalytic domains are characterized by positive co-operativity. Bioinformatics analysis pinpointed a conserved arginine residue at the interface of the regulatory and catalytic domains in bacterial CBS-PPases as potentially involved in enzyme regulation. The importance of this residue was assessed by site-directed mutagenesis using the CBS-PPase from Desulfitobacterium hafniense (dhPPase) as a model. The mutants R276A, R276K and R276E were constructed and purified, and the impact of the respective mutation on catalysis, nucleotide binding and regulation was analysed. Overall, the effects decreased in the following order R276A > R276E > R276K. The variants retained ≥50% catalytic efficiency but exhibited reduced kinetic co-operativity or even its inversion (R276A). Negative co-operativity was retained in the R276A variant in the presence of mononucleotides but was reversed by diadenosine tetraphosphate. Positive nucleotide-binding co-operativity was retained in all variants but the R276A and R276E variants exhibited a markedly reduced affinity to AMP and ADP and greater residual activity at their saturating concentrations. The R276A substitution abolished activation by ATP and diadenosine tetraphosphate, while preserving the ability to bind them. The results suggest that the H-bond formed by the Arg276 sidechain is essential for signal transduction between the regulatory and catalytic domains within one subunit and between the catalytic but not regulatory domains of different subunits.

journal_name

Arch Biochem Biophys

journal_title

Archives of biochemistry and biophysics

authors

Anashkin VA,Orlov VN,Lahti R,Baykov AA

doi

10.1016/j.abb.2018.11.024

subject

Has Abstract

pub_date

2019-02-15 00:00:00

pages

40-48

eissn

0003-9861

issn

1096-0384

pii

S0003-9861(18)30826-9

journal_volume

662

pub_type

杂志文章

在线工具

An arginine residue involved in allosteric regulation of cystathionine β-synthase (CBS) domain-containing pyrophosphatase.