title: Kinetic and structural characterization of an alternatively spliced variant of human mitochondrial 5'(3')-deoxyribonucleotidase.
abstract: Human mitochondrial 5'(3')-deoxyribonucleotidase (mdN) catalyzes dephosphorylation of nucleoside monophosphates, and thus helps maintain homeostasis of deoxynucleosides required for mitochondrial DNA synthesis. Mature mdN is a 23-kDa dimeric protein with highest expression levels in the heart, brain and skeletal muscle. We have identified an alternative splice variant of the mdN gene containing an 18-nucleotide insertion encoding 6 amino acids (GKWPAT) at the 3'-end of the penultimate exon 4. We recombinantly expressed this enzyme variant and characterized its biochemical and kinetic properties as well as its three-dimensional structure. Our high-resolution (1.27 Å) crystal structure revealed that the insertion forms a loop located in the vicinity of the active site pocket and affects enzyme kinetic parameters as well as protein thermal stability.
authors: Institute of Organic Chemistry and Biochemistry and.
authors: Petr
authors: P
authors: Pachl
authors: Milan
authors: M
authors: Fábry
authors: Václav
authors: V
authors: Veverka
authors: Jiří
authors: J
authors: Brynda
authors: Pavlína
authors: P
authors: Řezáčová
mesh_terms: D015720:5'-Nucleotidase / Q000737:chemistry* / Q000235:genetics; D017398:Alternative Splicing; D020134:Catalytic Domain; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005091:Exons; D015870:Gene Expression; D006801:Humans; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics; D007700:Kinetics; D024101:Mitochondrial Proteins / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics
chemical_list: D007527:Isoenzymes; D024101:Mitochondrial Proteins; D011994:Recombinant Proteins; C063766:5'(3')-nucleotidase; D015720:5'-Nucleotidase
keywords: 5′(3′)-deoxyribonucleotidase; alternative splicing; crystal structure; hydrolase; mitochondria