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Titolo:
X-RAY-ABSORPTION FINE-STRUCTURE AS A MONITOR OF ZINC COORDINATION SITES DURING OOGENESIS OF XENOPUS-LAEVIS
Autore:
AULD DS; FALCHUK KH; ZHANG K; MONTORZI M; VALLEE BL;
Indirizzi:
HARVARD UNIV,SCH MED,CTR BIOCHEM & BIOPHYS SCI & MED,250 LONGWOOD AVEBOSTON MA 02115 HARVARD UNIV,SCH MED,DEPT PATHOL BOSTON MA 02115 HARVARD UNIV,SCH MED,DEPT MED BOSTON MA 02115 BRIGHAM & WOMENS HOSP BOSTON MA 02115 UNIV PENN,INST BIOSTRUCT,UNIV CITY SCI CTR PHILADELPHIA PA 19104 UNIV PENN,INST BIOSTRUCT,DEPT BIOCHEM & BIOPHYS PHILADELPHIA PA 19104
Titolo Testata:
Proceedings of the National Academy of Sciences of the United Statesof America
fascicolo: 8, volume: 93, anno: 1996,
pagine: 3227 - 3231
SICI:
0027-8424(1996)93:8<3227:XFAAMO>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
CARBOXYPEPTIDASE-A; ACTIVE-SITE; BINDING; OOCYTE; LIPOVITELLIN; IRON;
Keywords:
VITELLOGENIN; LIPOVITELLIN; DEVELOPMENT; TRANSCRIPTION FACTOR;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
26
Recensione:
Indirizzi per estratti:
Citazione:
D.S. Auld et al., "X-RAY-ABSORPTION FINE-STRUCTURE AS A MONITOR OF ZINC COORDINATION SITES DURING OOGENESIS OF XENOPUS-LAEVIS", Proceedings of the National Academy of Sciences of the United Statesof America, 93(8), 1996, pp. 3227-3231

Abstract

The x-ray absorption fine structure (XAFS) zinc K-edge steps for intact stages I,II and V,VI Xenopus laevis oocytes demonstrate that the zinc concentration is about 3 and 1 mM, respectively, However, the chi(k) function for the early stage oocytes differs markedly from that for the late one, Analysis of the XAFS data for stage I,II oocytes indicates that zinc is bound to 2.0 +/- 0.5 sulfur atoms at an average coordination distance of 2.29 +/- 0.02 Angstrom and 2.0 +/- 0.5 nitrogen or oxygen (N/O) atoms at 2.02 +/- 0.02 Angstrom, In marked contrast, in stage V,VI oocytes, zinc is bound to 4.1 +/- 0.4 N/O atoms at an average distance of 1.98 +/- 0.01 Angstrom. Our previous studies demonstrated that 90% of the zinc in stage VI oocytes is sequestered within yolk platelets, associated with a single molecule, lipovitellin, the proteolytically processed product of vitellogenin. XAFS analysis of yolk platelets, lipovitellin, and vitellogenin demonstrates that zinc is boundto 4.0 +/- 0.5 N/O ligands at an average distance of 1.98 +/- 0.01 Angstrom in each case, identical to that of stage V,VI oocytes, The higher shell contributions in the Fourier transforms indicate that two of the N/O zinc ligands are His in both stage V,VI and I,II oocytes, The results show that in stage I,II oocytes, there is a high concentrationof a zinc protein whose zinc coordination site likely is composed of (His)(2)(Cys)(2), such as, e,g,, TFIIIA. As the oocytes develop, the predominant zinc species becomes one that exhibits the (His)(2)(N/O)(2)zinc site found in lipovitellin, Hence, the ligands to the zinc atomsin intact oocytes and the changes that take place as a function of oogenesis and after their fertilization, during embryogenesis, now can be examined and explored.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 12/08/20 alle ore 20:54:33