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Titolo:
SPECTROSCOPIC IDENTIFICATION OF A DINUCLEAR METAL CENTER IN MANGANESE(II)-ACTIVATED AMINOPEPTIDASE-P FROM ESCHERICHIA-COLI - IMPLICATIONS FOR HUMAN PROLIDASE
Autore:
ZHANG LB; CROSSLEY MJ; DIXON NE; ELLIS PJ; FISHER ML; KING GF; LILLEY PE; MACLACHLAN D; PACE RJ; FREEMAN HC;
Indirizzi:
UNIV SYDNEY,SCH CHEM SYDNEY NSW 2006 AUSTRALIA UNIV SYDNEY,SCH CHEM SYDNEY NSW 2006 AUSTRALIA AUSTRALIAN NATL UNIV,RES SCH CHEM CANBERRA ACT 0200 AUSTRALIA UNIV SYDNEY,DEPT BIOCHEM SYDNEY NSW 2006 AUSTRALIA AUSTRALIAN NATL UNIV,DEPT CHEM CANBERRA ACT 0200 AUSTRALIA
Titolo Testata:
JBIC. Journal of biological inorganic chemistry
fascicolo: 5, volume: 3, anno: 1998,
pagine: 470 - 483
SICI:
0949-8257(1998)3:5<470:SIOADM>2.0.ZU;2-Z
Fonte:
ISI
Lingua:
ENG
Soggetto:
BINUCLEAR MANGANESE CLUSTER; PIG-KIDNEY PROLIDASE; METHIONINE AMINOPEPTIDASE; NUCLEOTIDE-SEQUENCE; LIVER ARGINASE; DNA-SEQUENCE; GENE; PROTEINS; DEFICIENCY; CLONING;
Keywords:
AMINOPEPTIDASE P; PROLIDASE; EPR SPECTROSCOPY; X-RAY ABSORPTION FINE STRUCTURE; MN2+-ACTIVATED ENZYME;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
58
Recensione:
Indirizzi per estratti:
Citazione:
L.B. Zhang et al., "SPECTROSCOPIC IDENTIFICATION OF A DINUCLEAR METAL CENTER IN MANGANESE(II)-ACTIVATED AMINOPEPTIDASE-P FROM ESCHERICHIA-COLI - IMPLICATIONS FOR HUMAN PROLIDASE", JBIC. Journal of biological inorganic chemistry, 3(5), 1998, pp. 470-483

Abstract

Electron paramagnetic resonance (EPR) spectra and X-ray absorption (EXAFS and XANES) data have been recorded for the manganese enzyme aminopeptidase P (AMPP, PepP protein) from Escherichia coli. The biologicalfunction of the protein, a tetramer of 50-kDa subunits, is the hydrolysis of N-terminal Xaa-Pro peptide bonds. Activity assays confirm thatthe enzyme is activated by treatment with Mn2+. The EPR spectrum of Mn2+-activated AMPP at liquid-He temperature is characteristic of an exchange-coupled dinuclear Mn(II) site, the Mn-Mn separation calculated from the zero-field splitting D of the quintet state being 3.5 (+/- 0.1) Angstrom. In the X-ray absorption spectrum of Mn2+-activated AMPP at the Mn K edge, the near-edge features are consistent with octahedrally coordinated Mn atoms in oxidation state +2. EXAFS data, limited to k less than or equal to 12 Angstrom(-1) by traces of Fe in the protein, are consistent with a single coordination shell occupied predominantly by O donor atoms at an average Mn-ligand distance of 2.15 Angstrom,but the possibility of a mixture of O and N donor atoms is not excluded. The Mn-Mn interaction at 3.5 Angstrom, is not detected in the EXAFS, probably due to destructive interference from light outer-shell atoms. The biological function, amino acid sequence and metal-ion dependence of E. coli AMPP are closely related to those of human prolidase, an enzyme that specifically cleaves Xaa-Pro dipeptides. Mutations that lead to human prolidase deficiency and clinical symptoms have been identified. Several known inhibitors of prolidase also inhibit AMPP. Whenthese inhibitors are added to Mn2+-activated AMPP, the EPR spectrum and EXAFS remain unchanged. It can be inferred that the inhibitors either do not bind directly to the Mn centres, or substitute for existing Mn ligands without a significant change in donor atoms or coordinationgeometry. The conclusions from the spectroscopic measurements on AMPPhave been verified by, and complement, a recent crystal structure analysis.

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Documento generato il 24/09/20 alle ore 20:27:32