Differences in hydration and association of helical Boc-Val-Ala-Leu-Aib-Val-Ala-Leu-(Val-Ala-Leu-Aib)2-OMe. xH2O in two crystalline polymorphs


Autoria(s): Karle, Isabella L; Flippen-Anderson, Judith L; Sukumar, Muppalla; Balaram, Padmanabhan
Data(s)

16/10/1992

Resumo

The 15-residue apolar peptide, Boc-Val-Ala-Leu-Aib-Val-Ala-Leu-(Val-Ala-Leu-Aib)h2a-sO Mebeen crystallized from 2-propanol-water (form I). The crystal parameters for I are as follows:C74H133N15018*2H20s,p ace group P21, a = 9.185 (6) A, b = 47.410 (3) A, c = 10.325 (9) A, @ = 91.47(2)O, 2 = 2, R = 6.3% for 4532 reflections observed >3aQ, resolution 0.94 A. The structure isalmost completely a-helical with eleven 5-1 hydrogen bonds and one 441 hydrogen bond nearthe N-terminus. The structure has been compared with a polymorph (form 11) obtained frommethanol-water (Karle, I. L.; Flippen-Anderson, J. L.; Uma, K.; Sukumar, M.; Balaram, P., J. An.Chem. SOC19. 90,112,9350-9356). The two forms differ in the extent of hydration; form I contains two water molecules in the head-to-tail region of helical columns, while form I1 is more extensively solvated, with the equivalent of 7.5 water molecules. The three-dimensional packing of helices is completely parallel in I and antiparallel in 11.

Formato

application/pdf

Identificador

http://eprints.iisc.ernet.in/33720/1/jm00099a016.pdf

Karle, Isabella L and Flippen-Anderson, Judith L and Sukumar, Muppalla and Balaram, Padmanabhan (1992) Differences in hydration and association of helical Boc-Val-Ala-Leu-Aib-Val-Ala-Leu-(Val-Ala-Leu-Aib)2-OMe. xH2O in two crystalline polymorphs. In: Journal of Medical Chemistry, 35 (21). pp. 3885-3889.

Publicador

American Chemical Society

Relação

http://pubs.acs.org/doi/abs/10.1021/jm00099a016

http://eprints.iisc.ernet.in/33720/

Palavras-Chave #Molecular Biophysics Unit
Tipo

Journal Article

PeerReviewed