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B Crews

Publications and source records attributed to B Crews.

4 recordsLinked to original sources

Bait region-thiol ester mapping in human alpha 2-macroglobulin.

The separations between aromatic residues in the bait region and nitroxide spin labels attached to the thiol ester-forming residues (Cys949 and Gln952) in human alpha 2-macroglobulin (alpha 2M) have been determined from paramagnetic broadening effects of the spin labels on bait region 1H NMR signals. We found that both the Cys949 and Gln952 residues are within 11-17 A of the aromatic residues in the bait region, with closer approach of some residues to the Gln952 spin label than to the spin label attached to Cys949. A model of the location of bait regions and thiol esters within an alpha 2M half-molecule is proposed that places the bait regions in the central region of alpha 2M at the interface between the subunits.

Electron Spin Resonance Spectroscopy↗

Selenium-dependent glutathione peroxidases from ovine and bovine erythrocytes occur as longer chain forms than previously recognized.

From the cDNA sequence of bovine glutathione peroxidase [G. T. Mullenbach, A. Tabrizi, B. D. Irvine, G. I. Bell, J. A. Tainer, and R. A. Hallewell (1988) Protein Eng. 2, 239-246], it is known that the full transcript represents a 205-residue protein with the N-terminal sequence of MCAAQRSAAALAAAAPRTV. However, a protein primary structure determination on what is believed to be the mature protein showed an N-terminal sequence of AAALAAAAPRTV [W. A. Günzler, G. J. Steffens, A. Grossmann, S. A. Kim, F. Otting, A. Wendel, and L. Flohe (1984) Hoppe-Seyler's Z. Physiol. Chem. 365, 195-212], suggesting processing of the N-terminal 7 residues to give the mature protein. It is shown here that the normal form of bovine erythrocyte glutathione peroxidase is most likely the full transcript lacking the N-terminal methionine, and that subsequent proteolysis during isolation results in formation first of the form characterized by Günzler et al. and then of two slightly smaller species, the smaller of which appears to be similar to that examined crystallographically [O. Epp, R. Ladenstein, and A. Wendel (1983) Eur. J. Biochem. 133, 51-69]. For ovine erythrocyte glutathione peroxidase the same behavior is seen, with initial isolation of a high-molecular-weight form that is subsequently proteolyzed to two intermediate forms and a final form that migrates at the same position on acrylamide gels as the lowest-molecular-weight form of the bovine enzyme. The contaminating protease can be inhibited by the addition of 10 mM EDTA, suggesting that it is a metalloprotease. Activity measurements on the intact and processed forms of the ovine enzyme show no significant differences with both hydrogen peroxide and t-butyl hydroperoxide as substrates. These results suggest that both bovine and ovine erythrocyte glutathione peroxidases consist of a globular core that is relatively resistant to proteolysis and an N-terminal tail of approximately 17 residues that seems to be exposed and is very sensitive to proteolysis. This tail, which contains many hydrophobic residues, is predicted to be largely alpha-helical and may be involved in anchoring the enzyme at or close to the membrane surface.

Amino Acid Sequence↗

Student health team project at the Wayside Chapel.

The student health teams were organized by the Australian Medical Students Association (AMSA) as the means of student involvement in community health projects. In July, 1976, at the Wayside Chapel several student health teams each consisting of a medical student, a nursing student, and a student social worker, began a friendly, non-judgemental "first aid" service for street people with health problems. The project lasted 12 weeks and aid was given to 76 people. An evaluation of the project appears below.

Attitude of Health Personnel↗