1ypa: Difference between revisions
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
[[Image:1ypa.jpg|left|200px]] | [[Image:1ypa.jpg|left|200px]] | ||
'''DIRECT OBSERVATION OF BETTER HYDRATION AT THE N-TERMINUS OF AN ALPHA-HELIX WITH GLYCINE RATHER THAN ALANINE AS N-CAP''' | {{Structure | ||
|PDB= 1ypa |SIZE=350|CAPTION= <scene name='initialview01'>1ypa</scene>, resolution 2.0Å | |||
|SITE= | |||
|LIGAND= | |||
|ACTIVITY= | |||
|GENE= | |||
}} | |||
'''DIRECT OBSERVATION OF BETTER HYDRATION AT THE N-TERMINUS OF AN ALPHA-HELIX WITH GLYCINE RATHER THAN ALANINE AS N-CAP''' | |||
==Overview== | ==Overview== | ||
| Line 7: | Line 16: | ||
==About this Structure== | ==About this Structure== | ||
1YPA is a [ | 1YPA is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Hordeum_vulgare Hordeum vulgare]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1YPA OCA]. | ||
==Reference== | ==Reference== | ||
Direct observation of better hydration at the N terminus of an alpha-helix with glycine rather than alanine as the N-cap residue., Harpaz Y, Elmasry N, Fersht AR, Henrick K, Proc Natl Acad Sci U S A. 1994 Jan 4;91(1):311-5. PMID:[http:// | Direct observation of better hydration at the N terminus of an alpha-helix with glycine rather than alanine as the N-cap residue., Harpaz Y, Elmasry N, Fersht AR, Henrick K, Proc Natl Acad Sci U S A. 1994 Jan 4;91(1):311-5. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/8278384 8278384] | ||
[[Category: Hordeum vulgare]] | [[Category: Hordeum vulgare]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| Line 19: | Line 28: | ||
[[Category: proteinase inhibitor(chymotrypsin)]] | [[Category: proteinase inhibitor(chymotrypsin)]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 15:25:45 2008'' | ||
Revision as of 16:25, 20 March 2008
| |||||||
| , resolution 2.0Å | |||||||
|---|---|---|---|---|---|---|---|
| Coordinates: | save as pdb, mmCIF, xml | ||||||
DIRECT OBSERVATION OF BETTER HYDRATION AT THE N-TERMINUS OF AN ALPHA-HELIX WITH GLYCINE RATHER THAN ALANINE AS N-CAP
OverviewOverview
The structural basis for the stability of N termini of helices has been analyzed by thermodynamic and crystallographic studies of three suitably engineered mutants of the barley chymotrypsin inhibitor 2 with Ser, Gly, or Ala at the N-cap position (residue 31). Each mutant has a well-organized shell of hydration of the terminal NH groups of the helix. The three structures are virtually superimposable (rms separations for all atoms, including the common water molecules, are 0.15-0.17 A) and show neither changes in conformation at the site of substitution nor changes in the crystal packing. The only changes on going from Ser-31 to Ala-31 to Gly-31 are in the position of a water molecule (Wat-116). This is bound to the Ser-O gamma atom in the Ser-31 structure but is in a weak hydrogen bonding position with the NH of residue 34 (O ... N = 3.28 A) in the Ala-31 mutant, partly replacing the strong Ser-31-O gamma ... N34 hydrogen bond (O ... N = 2.65 A). The corresponding water molecule completely replaces the Ser hydroxyl hydrogen bond to N34 on mutation to Gly (2.74 A). The only other change between the three structures is an additional water molecule in the Ala-31 structure (Wat-150) that partly compensates for the weak Wat-116 ... N34 hydrogen bond. Perturbation of solvation by the side chain of Ala is consistent with earlier hypotheses on the importance of exposure of the termini of helices to the aqueous solvent.
About this StructureAbout this Structure
1YPA is a Single protein structure of sequence from Hordeum vulgare. Full crystallographic information is available from OCA.
ReferenceReference
Direct observation of better hydration at the N terminus of an alpha-helix with glycine rather than alanine as the N-cap residue., Harpaz Y, Elmasry N, Fersht AR, Henrick K, Proc Natl Acad Sci U S A. 1994 Jan 4;91(1):311-5. PMID:8278384
Page seeded by OCA on Thu Mar 20 15:25:45 2008