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Digitale Medien

Crystallographic analysis of oxygenated and deoxygenated states of arthropod hemocyanin shows unusual differences (1994)

Magnus, Karen A. ; Hazes, Bart ; Ton-That, Hoa ; [weitere]

New York, NY : Wiley-Blackwell

Proteins: Structure, Function, and Genetics 19 (1994), S. 302-309

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ISSN: 0887-3585

Schlagwort(e): dinuclear copper site ; hemocyanin ; oxygen binding ; allosteric regulation ; Chemistry ; Biochemistry and Biotechnology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Medizin

Notizen: The X-ray structure of an oxygenated hemocyanin molecule, subunit II of Limulus polyphemus hemocyanin, was determined at 2.4 Å resolution and refined to a crystallographic R-factor of 17.1%. The 73-kDa subunit crystallizes with the symmetry of the space group R32 with one subunit per asymmetric unit forming hexamers with 32 point group symmetry. Molecular oxygen is bound to a dinuclear copper center in the protein's second domain, symmetrically between and equidistant from the two copper atoms. The copper-copper distance in oxygenated Limulus hemocyanin is 3.6 ± 0.2 Å, which is surprisingly 1 Å less than that seen previously in deoxygenated Limulus polyphemus subunit II hemocyanin (Hazes et al., Protein Sci. 2:597, 1993). Away from the oxygen binding sites, the tertiary and quaternary structures of oxygenated and deoxygenated Limulus subunit II hemocyanins are quite similar. A major difference in tertiary structures is seen, however, when the Limulus structures are compared with deoxygenated Panulirus interruptus hemocyanin (Volbeda, A., Hol, W. G. J. J. Mol. Biol. 209:249, 1989) where the position of domain 1 is rotated by 8° with respect to domains 2 and 3. We postulate this rotation plays an important role in cooperativity and regulation of oxygen affinity in all arthropod hemocyanins. © 1994 Wiley-Liss, Inc.

Zusätzliches Material: 4 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/prot.340190405

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Digitale Medien

Macromolecular cues in marine systems (1986)

Rittschof, Dan ; Bonaventura, Joseph

Springer

Journal of chemical ecology 12 (1986), S. 1013-1023

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ISSN: 1573-1561

Schlagwort(e): Marine animals ; macromolecules ; peptides ; glycoproteins ; behavior ; prey detection ; site selection ; metamorphosis ; biopolymers

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie , Chemie und Pharmazie

Notizen: Abstract A review of the roles of biopolymers as marine chemical cues is presented. The goal of the review is to provide a context within which to view present research and to provide insight into future research potential for macromolecules in marine chemical ecology. The roles of peptides, proteins, glycoproteins, proteoglycans, lectins, and mucopolysaccharides are discussed. Biological events mediated include: larval settlement and metamorphosis, gamete attraction, predator-prey interactions, alarm responses, feeding responses, nonfood resource acquisition, trail following, and larval-release behavior. Molecular origins, transmission, modulation, and multifunctionality of cues are discussed and illustrated with specific examples. The advantages of biopolymers, especially peptides and proteins, as specific cues in marine systems derive from their solubility, specific information content (due to the asymmetric nature of the monomer and the wordlike information content of the primary structure of the polymer), distance transmission in water by bulk flow rather than diffusion, relatively high signal-to-noise ratio, and common occurrence as structural and metabolic components of all living organisms.