Minimal structural requirements for root effect: Crystal structure of the cathodic hemoglobin isolated from the Antarctic fish Trematomus newnesi(624 views) Mazzarella L, Bonomi G, Lubrano MC, Merlino A, Riccio A, Vergara A, Vitagliano L, Verde C, Di Prisco G
Proteins (ISSN: 0887-3585, 1097-0134, 1097-0134electronic), 2006 Feb 1; 62(2): 316-321.
Keywords: Antarctic Fish Hemoglobin, Cooperativity, Root Effect, Aspartic Acid, Bohr Effect Protein, Histidine, Isoleucine, Oxygen, Root Effect Protein, Serine, Unclassified Drug, Amino Acid Sequence, Binding Affinity, Crystal Structure, Hydrogen Bond, Molecular Interaction, Nonhuman, Priority Journal, Protein Function, Protein Isolation, Protein Stability, Protein Structure, Trematomus Newnesi, Animals, Antarctic Regions, Carboxyhemoglobin, Crystallization, Crystallography, X-Ray, Electrons, Macromolecular Substances, Models, Protein Conformation, Secondary,
Affiliations: *** IBB - CNR ***
Dipartimento di Chimica, Universitá degli Studi di Napoli Federico II, Naples, Italy
Istituto di Biostrutture e Bioimmagini, CNR, Naples, Italy
Centro Regionale di Competenza Bioteknet, Complesso Ristrutturato S. Andrea delle Dame, Naples, Italy
Istituto di Biochimica delle Proteine, CNR, Naples, Italy
References: Not available.
Minimal structural requirements for root effect: Crystal structure of the cathodic hemoglobin isolated from the Antarctic fish Trematomus newnesi
The cathodic hemoglobin component of the Antarctic fish Trematomus newnesi (HbCTn) is a Root-effect protein. The interpretation of its functional properties in relation to its sequence is puzzling. Indeed, HbCTn sequence is characterized by an extremely low histidyl content, and in particular by the lack of His146 beta and His69 beta, which are believed to be important in Bohr and Root effects, respectively. Furthermore, previous analyses suggested that the local environment of Asp95 alpha, Asp99 beta, and Asp101 beta should not be appropriate for the formation of Asp-Asp interactions, which are important for the Root effect. Here, we report the high-resolution crystal structure of the deoxy form of HbCTn. Our data provide a structural interpretation for the very low oxygen affinity of the protein and insights into the structural determinants of the Root effect protein. The structure demonstrates that the presence of Ile41 alpha and Ser97 alpha at the alpha(1)beta(2) interface does not prevent the formation of the inter-Asp interactions in HbCTn, as previous studies had suggested. The present data indicate that the hydrogen bond formed between Asp95a and Asp101 beta, which is stabilized by Asp99 beta, is per se sufficient to generate the Root effect, and it is the minimal structural requirement needed for the design of Root-effect Hbs.
Minimal structural requirements for root effect: Crystal structure of the cathodic hemoglobin isolated from the Antarctic fish Trematomus newnesi
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Minimal structural requirements for root effect: Crystal structure of the cathodic hemoglobin isolated from the Antarctic fish Trematomus newnesi