>
>Len,
>
>I picked up your question re ligation methods from the abrf. Steve Kent at
>Gryphon has a method coupling at X-Cys junctions (native chemical ligation;
>also published on by Jimmy Tam). It works well even in guanidine
>hydrochloride. I don't see the merit of adding back in back-bone protection;
>the real merit is the total lack of protection,enhancing solubility and
>eliminating further synthetic steps. The limitations are the restriction to
>terminal Cys, and incompatibility with Fmoc chemistry. The latter is a "hot"
>topic. George Barany, Bob Ramage, Syntem (in
>France), Hojo have their own variations, but it is a tough problem, and
>nobody has the right mix yet.
>Dear Len:
>
>Somebody forwarded me your query from the bulletin board, about the
>practical utility of chemical ligation of unprotected peptides.
>
>Yep, it works.
>
>We have used chemical ligation of unprotected peptide segments to make more
>than 300 proteins ranging in length from ~50 to ~225 residues. It's the best
>thing since sliced bread.
>
>See: "NMR structure of minimized human
>agouti-related protein prepared by total chemical synthesis." K.A. Bolin,
>D.J. Anderson, J.A. Trulson, I. Gantz, D.A. Thompson, J. Wilken, S.B.H.
>Kent, G.L. Milhauser, FEBS Letters, 451, 125-131 (1999).
>
>The best methodology papers are: "Modulation of reactivity in native
>chemical ligation through the use of thiol additives." P. E. Dawson, M.
>Churchill, M. R. Ghadiri, S.B.H. Kent. J.Am.Chem.Soc., 119, 4325-29 (1997);
>and, "Protein Synthesis by Native Chemical Ligation: Expanded Scope by Using
>Straightforward Methodology ", Hackeng, T. M., Griffin, J. H., Dawson, P.
>E. 1999. Proc. Natl. Acad. Sci. USA. 96: 10068-10073
>
>Also, don't forget the original paper that started it all: "Synthesis of
>proteins by native chemical ligation." Philip E. Dawson, Tom W. Muir, Ian
>Clark-Lewis, Stephen B.H. Kent, Science, 266, 776-779 (1994). It's all in
>there.
>
>Have fun.
>
>Regards,
>
>Steve Kent
*********************************************************************
Dr Len C. Packman
Assistant Director of Research
Protein and Nucleic Acid Chemistry Facility
Department of Biochemistry
University of Cambridge
80 Tennis Court Road
Old Addenbrookes Site
Cambridge, CB2 1GA, UK
Tel: +44 (1223) 333639
FAX: +44 (1223) 766002
e-mail: lcp2@mole.bio.cam.ac.uk
Visit my WWW page at http://www.bio.cam.ac.uk/proj/adr/PNAC/pnac.html