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Biomedical subjects

T Crawford

Publications and source records attributed to T Crawford.

33 records · Page 2Linked to original sources
PubMed1984

Interaction of glycophorin with phosphatidylserine: a Fourier transform infrared investigation.

Glycophorin, from the human erythrocyte membrane, has been isolated in pure form and reconstituted into unilamellar vesicles with bovine brain phosphatidylserine (PS). Fourier transform infrared spectroscopy has been used to monitor the protein conformation as well as the effect of protein on lipid order and melting. Glycophorin, at levels of 1 mol %, nearly abolishes the gel to liquid-crystal phase transition seen in pure PS vesicles between 8 and 16 degrees C by inducing significant disorder into the lipid gel phase. A transition of reduced magnitude remains between 14 and 22 degrees C in the lipid/protein complexes. Evidence is presented for specific interaction of glycophorin with the interfacial region of PS. In general, the effects on lipid melting produced by protein at the 1 mol % level are more pronounced than those noted in a previous study of glycophorin/phosphatidylcholine interactions [ Mendelsohn , R., Dluhy , R. A., Taraschi , T., Cameron, D., & Mantsch , H.H. (1981) Biochemistry 20, 6699-6706]. Two bands are observed for the protein amide I (C = O stretching) mode. A main feature at 1653 cm-1 indicates that the bulk of the secondary structure is random coil or alpha-helical. A weaker shoulder at 1675 cm-1 suggests the occurrence of a small proportion of the beta-sheet form. The results confirm circular dichroism studies of Schulte & Marchesi (1979) [ Schulte , T.H., & Marchesi , V.T. (1979) Biochemistry 18, 275-280]. Fourier transform infrared (FT-IR) studies of a ternary complex of PS/dipalmitoyl-phosphatidylcholine- d62 (DPPC- d62 )/glycophorin indicate that the glycophorin preferentially interacts with the PS component.(ABSTRACT TRUNCATED AT 250 WORDS)

Erythrocyte Membrane↗
PubMed1983

Characteristics of chondroitin sulfate proteoglycans of differentiating nonchondrogenic tissues.

The chondroitin 4- and 6-sulfate proteoglycan monomers from two differentiating tissues (brain and muscle of 14-day chick embryos) were compared by indirect means, including use of chondroitinase AC, with the major class of cartilage chondroitin sulfate proteoglycan monomers. In addition to slower sedimentation in sucrose density gradients, the monomers from both noncartilaginous tissues have longer chondroitin sulfate chains and exhibit little difference in the susceptibilities of their core proteins to papain and trypsin, in contrast to the cartilage monomer. However, slight differences in average sizes and polydispersity of fragments formed by enzyme treatments and beta-elimination were found between the proteochondroitin sulfate monomers of embryonic brain and muscle. Although the chondroitin sulfate chains are attached to separate tryptic peptides from the majority of other sulfated glycosaminoglycans in the noncartilaginous tissues, it is still uncertain whether these units form part of separate proteoglycan monomers.

Animals↗