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Helix capping in the GCN4 leucine zipper.
J Mol Biol. 1999 May 14; 288(4):743-52.JM

Abstract

Capping interactions associated with specific sequences at or near the ends of alpha-helices are important determinants of the stability of protein secondary and tertiary structure. We investigate here the role of the helix-capping motif Ser-X-X-Glu, a sequence that occurs frequently at the N termini of alpha helices in proteins, on the conformation and stability of the GCN4 leucine zipper. The 1.8 A resolution crystal structure of the capped molecule reveals distinct conformations, packing geometries and hydrogen-bonding networks at the amino terminus of the two helices in the leucine zipper dimer. The free energy of helix stabilization associated with the hydrogen-bonding and hydrophobic interactions in this capping structure is -1.2 kcal/mol, evaluated from thermal unfolding experiments. A single cap thus contributes appreciably to stabilizing the terminated helix and thereby the native state. These results suggest that helix capping plays a further role in protein folding, providing a sensitive connector linking alpha-helix formation to the developing tertiary structure of a protein.

Authors+Show Affiliations

Department of Biochemistry, Weill Medical College of Cornell University, New York, NY, 10021, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

10329176

Citation

Lu, M, et al. "Helix Capping in the GCN4 Leucine Zipper." Journal of Molecular Biology, vol. 288, no. 4, 1999, pp. 743-52.
Lu M, Shu W, Ji H, et al. Helix capping in the GCN4 leucine zipper. J Mol Biol. 1999;288(4):743-52.
Lu, M., Shu, W., Ji, H., Spek, E., Wang, L., & Kallenbach, N. R. (1999). Helix capping in the GCN4 leucine zipper. Journal of Molecular Biology, 288(4), 743-52.
Lu M, et al. Helix Capping in the GCN4 Leucine Zipper. J Mol Biol. 1999 May 14;288(4):743-52. PubMed PMID: 10329176.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Helix capping in the GCN4 leucine zipper. AU - Lu,M, AU - Shu,W, AU - Ji,H, AU - Spek,E, AU - Wang,L, AU - Kallenbach,N R, PY - 1999/5/18/pubmed PY - 1999/5/18/medline PY - 1999/5/18/entrez SP - 743 EP - 52 JF - Journal of molecular biology JO - J Mol Biol VL - 288 IS - 4 N2 - Capping interactions associated with specific sequences at or near the ends of alpha-helices are important determinants of the stability of protein secondary and tertiary structure. We investigate here the role of the helix-capping motif Ser-X-X-Glu, a sequence that occurs frequently at the N termini of alpha helices in proteins, on the conformation and stability of the GCN4 leucine zipper. The 1.8 A resolution crystal structure of the capped molecule reveals distinct conformations, packing geometries and hydrogen-bonding networks at the amino terminus of the two helices in the leucine zipper dimer. The free energy of helix stabilization associated with the hydrogen-bonding and hydrophobic interactions in this capping structure is -1.2 kcal/mol, evaluated from thermal unfolding experiments. A single cap thus contributes appreciably to stabilizing the terminated helix and thereby the native state. These results suggest that helix capping plays a further role in protein folding, providing a sensitive connector linking alpha-helix formation to the developing tertiary structure of a protein. SN - 0022-2836 UR - https://www.unboundmedicine.com/medline/citation/10329176/Helix_capping_in_the_GCN4_leucine_zipper_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0022-2836(99)92707-9 DB - PRIME DP - Unbound Medicine ER -