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At least 937 records · Page 52Linked to original sources
PubMed1996

Specificity studies of bacterial sulfatases by means of structurally defined sulfated oligosaccharides isolated from shark cartilage chondroitin sulfate D.

Chondro-4-sulfatase and chondro-6-sulfatase from Proteus vulgaris and delta-hexuronate-2-sulfatase from Flavobacterium heparinum are potentially useful tools for structural studies of chondroitin sulfate and dermatan sulfate. Their substrate specificities were investigated with various structurally defined, sulfated hexasaccharides isolated from chondroitin sulfate as described in the accompanying report [Sugahara, K., Nadanaka, S., Takeda, K. & Kojima, T. (1996) Eur. J. Biochem. 239, 871-880]. The results indicated that delta-hexuronate-2-sulfatase released an ester sulfate from the C2 position of the delta-hexuronate residue located at the non-reducing terminus, while chondro-6-sulfatase removed an ester sulfate from the C6 position of the GalNAc residue at the reducing end of the hexasaccharides. Chondro-4-sulfatase acted preferentially on an ester sulfate on the C4 position of the GalNAc residue at the reducing end under mild incubation conditions, but also released a sulfate group under harsh conditions from the C4 position of the GalNAc residue at the internal positions of the hexasaccharide chains, unless the GalNAc residue had another ester sulfate on its C6 position. The results demonstrated the usefulness of the sulfatases as tools for the structural characterization of chondroitin sulfate oligosaccharides.

Animals↗
PubMed2004

Crystal structure of a shark single-domain antibody V region in complex with lysozyme.

Cartilaginous fish are the phylogenetically oldest living organisms known to possess components of the vertebrate adaptive immune system. Key to their immune response are heavy-chain, homodimeric immunoglobulins called new antigen receptors (IgNARs), in which the variable (V) domains recognize antigens with only a single immunoglobulin domain, akin to camelid heavy-chain V domains. The 1.45 angstrom resolution crystal structure of the type I IgNAR V domain in complex with hen egg-white lysozyme (HEL) reveals a minimal antigen-binding domain that contains only two of the three conventional complementarity-determining regions but still binds HEL with nanomolar affinity by means of a binding interface comparable in size to conventional antibodies.

Animals↗
PubMed1969

Shark pit organs: response to chemicals.

Nerve fibers from pit organs and canal neuromasts are distinguished by the nature of their electrophysiological response to mechanical and chemical stimulation. Pit organs respond to touch but have a relatively high threshold compared with canal neuromasts. They respond readily to sodium and potassium chloride solutions, the rate of discharge increasing with the concentration of the solution. Order of effectiveness with 1 molar solutions of monovalent cations is as follows: potassium, rubidium > sodium, ammonium > cesium, lithium. Anions are ineffective. Divalent cations such as calcium and magnesium are inhibitory. Responses to acid, sugar, and quinine are either very slight or inhibitory.

Animals↗