1CE9
HELIX CAPPING IN THE GCN4 LEUCINE ZIPPER
Summary for 1CE9
| Entry DOI | 10.2210/pdb1ce9/pdb |
| Descriptor | PROTEIN (GCN4-PMSE) (2 entities in total) |
| Functional Keywords | helix capping, leucine zipper, hydrogen bonding, thermal stability, protein folding |
| Cellular location | Nucleus: P03069 |
| Total number of polymer chains | 4 |
| Total formula weight | 16142.65 |
| Authors | Lu, M.,Shu, W.,Ji, H.,Spek, E.,Wang, L.-Y.,Kallenbach, N.R. (deposition date: 1999-03-18, release date: 1999-03-25, Last modification date: 2023-08-09) |
| Primary citation | Lu, M.,Shu, W.,Ji, H.,Spek, E.,Wang, L.,Kallenbach, N.R. Helix capping in the GCN4 leucine zipper. J.Mol.Biol., 288:743-752, 1999 Cited by PubMed 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. PubMed: 10329176DOI: 10.1006/jmbi.1999.2707 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.8 Å) |
Structure validation
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