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Titolo:
Structural and functional analysis of the two haemoglobins of the Antarctic seabird Catharacta maccormicki - Characterization of an additional phosphate binding site by molecular modelling
Autore:
Tamburrini, M; Riccio, A; Romano, M; Giardina, B; di Prisco, G;
Indirizzi:
CNR, Inst Prot Biochem & Enzymol, I-80125 Naples, Italy CNR Naples ItalyI-80125 t Prot Biochem & Enzymol, I-80125 Naples, Italy Univ Cattolica Sacro Cuore, Fac Med, Inst Chem & Clin Chem, Rome, Italy Univ Cattolica Sacro Cuore Rome Italy nst Chem & Clin Chem, Rome, Italy
Titolo Testata:
EUROPEAN JOURNAL OF BIOCHEMISTRY
fascicolo: 19, volume: 267, anno: 2000,
pagine: 6089 - 6098
SICI:
0014-2956(200010)267:19<6089:SAFAOT>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
AMINO-ACID-SEQUENCE; NOTOTHENIA-CORIICEPS-NEGLECTA; HUMAN DEOXYHEMOGLOBIN; CRYSTAL-STRUCTURE; OXYGEN-AFFINITY; HEMOGLOBIN; HEXAKISPHOSPHATE; ADAPTATION; PROTEINS; BIRDS;
Keywords:
Antarctica; Bohr effect; haemoglobin; homology modelling; phosphate binding;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
27
Recensione:
Indirizzi per estratti:
Indirizzo: di Prisco, G CNR, Inst Prot Biochem & Enzymol, Via Marconi 12, I-80125 Naples, Italy CNR Via Marconi 12 Naples Italy I-80125 -80125 Naples, Italy
Citazione:
M. Tamburrini et al., "Structural and functional analysis of the two haemoglobins of the Antarctic seabird Catharacta maccormicki - Characterization of an additional phosphate binding site by molecular modelling", EUR J BIOCH, 267(19), 2000, pp. 6089-6098

Abstract

The amino-acid sequence and the oxygen-binding properties of the two haemoglobins of the Antarctic seabird south polar skua have been investigated. The two haemoglobins showed peculiar functional features, which were probably acquired to meet special needs in relation to the extreme environmental conditions. Both haemoglobins showed a weak alkaline Bohr effect which, during prolonged flight, may protect against sudden and uncontrolled stripping of oxygen in response to acidosis. We suggest that a weak Bohr effect in birds may reflect adaptation to extreme life conditions. The values of heat of oxygenation suggest different functional roles of the two haemoglobins. The experimental evidence suggests that both haemoglobins may bind phosphateat two distinct binding sites. In fact, analysis of the molecular models revealed that an additional phosphate binding site, formed by residues NA1 alpha, G6 alpha and HC3 alpha, is located between the two cr chains. This additional site may act as an entry/leaving site, thus increasing the probability of capturing phosphate and transferring it to the main binding site located between the two beta chains by means of a site-site migratory mechanism, thereby favouring the release of oxygen. It is suggested that most haemoglobins possess an additional phosphate binding site, having such a role in oxygen transport.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/04/20 alle ore 12:48:22