5-Lactoglobulin folding

Kuwata, K., Shastry, R., Cheng, H., Hoshino, M., Batt, C. A., Goto, Y., and Roder, H. (2001). Structural and kinetic characterization of early folding events in beta-lactoglobulin. Nat. 

This chapter has reviewed the application of ROA to studies of unfolded proteins, an area of much current interest central to fundamental protein science and also to practical problems in areas as diverse as medicine and food science. Because the many discrete structure-sensitive bands present in protein ROA spectra, the technique provides a fresh perspective on the structure and behavior of unfolded proteins, and of unfolded sequences in proteins such as A-gliadin and prions which contain distinct structured and unstructured domains. It also provides new insight into the complexity of order in molten globule and reduced protein states, and of the more mobile sequences in fully folded proteins such as /1-lactoglobulin. With the promise of commercial ROA instruments becoming available in the near future, ROA should find many applications in protein science. Since many gene sequences code for natively unfolded proteins in addition to those coding for proteins with well-defined tertiary folds, both of which are equally accessible to ROA studies, ROA should find wide application in structural proteomics. 

Mother s milk is an often coined term for products that mimic the natural mother s milk contents. Actual human mother s milk contains about 40-50% casein and 50-60% whey, and about 17% lactoferrin with no beta-lactoglobulin. As I said earlier, mother s milk contains alfa lactoglobulin. This is very different from cow s milk which contains about 80% casein and 20% whey with 1% lactoferrin being average. Lactoferrin has anti-viral activity, and is a potent immune system booster. Obviously this is an advantage for new born human (rug rats) since they lack complete immune system functions. Remember the fact that human mother s milk dominant protein fraction is alfa-lactalbumin Well, there is a research project on going which claims acid folded alfa-... 

Chobert, J.-M., Briand, L., Grinberg, V., and Haertle, T. 1995. Impact of esterification on the folding and susceptibility to peptic proteolysis of (3-lactoglobulin. Biochim. Biophys. Acta 1248, 170-176. 

Slade and Vulfson have shown that the catalytic activity of native BSA in the dehydrofluorination reaction in aqueous media is greater than that reported for catalytic antibodies and molecularly imprinted polymers [30]. These authors therefore imprinted ]S-lactoglobulin and papain using A-isopropyl-4-nitrobenzyl amine as the transition state analogue. The catalytic activity of the imprinted proteins was evaluated in the dehydrofluorination reaction using acetonitrile as the reaction medium. A three fold rate enhancement in the A eat value vis-d-vis non-imprinted proteins was observed. 

Fernandez A, Colubri A, Berry RS (2000) Topology to Geometry in protein folding Beta-lactoglobulin. Proc Natl Acad Sci USA 97 14062-14066... 

Limited Proteolysis of Solvent-Induced Folding Changes of /3-Lactoglobulin... 

Shiraki K, Nishikawa K, and Goto W. Trifluroethanol Induced Stabilization of the a-helical structure of (3-lactoglobulin Implications for Non-hierachical Protein Folding./Mo/Pio/1995 245 180-194. 

Figure 10.18 shows the spectra of native and denatured /J-lactoglobulin A (j3-LG), native myoglobin, and a -casein in DjO solution. In the spectra at pD 1.0 and 7.5 (actually these are pD s 1.4 and 7.9 respectively after the proper corrections are made), the amide I band is like the one observed in the dry film (1632cm with weaker shoulders near 1650 and 1685cm ). In the denatured form (pD 11.5, corrected to 11.9), a single amide I band is displayed at 1643 cm Randomly folded a -casein (Herskovits and Mescanti, 1965) is known to give an almost identical band. 

Myoglobin in DjO at pD 6.6 (corrected to 7.0) has an amide I band at 1650 cm, characteristic of a-helical structure. Myoglobin is known to have at least 77% a-helical structure (Kendrew et al., 1960). Timasheff and Susi s (1966) data indicate that in DjO solution the )S-conformation and the a-helical conformation produce amide I bands at the same frequencies as in dry films. Randomly folded proteins (a -casein and denatured ) -lactoglobulin) give rise to a sharp band centering at 1643 cm... 

Slow hydrogen-deuterium exchange (see Chapter 11) of native -lactoglobulin in DjO, pD 1.0 (corrected to 1.4) allowed the amide II band ( 1550 cm ) to remain and be seen in one sample of the lactoglobulin (Fig. 10.18, top curve) which was run immediately after preparation. The presence of this band shows that the native protein must be quite compact. No such bands are observed in denatured lactoglobulin or in a -casein, which have loose randomly folded structures. 

---