1eeu: Difference between revisions
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
[[Image:1eeu.jpg|left|200px]] | [[Image:1eeu.jpg|left|200px]] | ||
<!-- | |||
The line below this paragraph, containing "STRUCTURE_1eeu", creates the "Structure Box" on the page. | |||
You may change the PDB parameter (which sets the PDB file loaded into the applet) | |||
or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |||
| | or leave the SCENE parameter empty for the default display. | ||
| | --> | ||
{{STRUCTURE_1eeu| PDB=1eeu | SCENE= }} | |||
}} | |||
'''M4L/Y(27D)D/Q89D/T94H mutant of LEN''' | '''M4L/Y(27D)D/Q89D/T94H mutant of LEN''' | ||
| Line 30: | Line 27: | ||
[[Category: Schiffer, M.]] | [[Category: Schiffer, M.]] | ||
[[Category: Stevens, F J.]] | [[Category: Stevens, F J.]] | ||
[[Category: | [[Category: Aspartic acid in beta-sheet]] | ||
[[Category: | [[Category: Human kappa-4 immunoglobulin light chain]] | ||
[[Category: | [[Category: Mutant]] | ||
[[Category: | [[Category: Protein stability]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 15:00:43 2008'' | |||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | |||
Revision as of 15:00, 2 May 2008
M4L/Y(27D)D/Q89D/T94H mutant of LEN
OverviewOverview
Asp residues are significantly under represented in beta-sheet regions of proteins, especially in the middle of beta-strands, as found by a number of studies using statistical, modeling, or experimental methods. To further understand the reasons for this under representation of Asp, we prepared and analyzed mutants of a beta-domain. Two Gln residues of the immunoglobulin light-chain variable domain (V(L)) of protein Len were replaced with Asp, and then the effects of these changes on protein stability and protein structure were studied. The replacement of Q38D, located at the end of a beta-strand, and that of Q89D, located in the middle of a beta-strand, reduced the stability of the parent immunoglobulin V(L) domain by 2.0 kcal/mol and 5.3 kcal/mol, respectively. Because the Q89D mutant of the wild-type V(L)-Len domain was too unstable to be expressed as a soluble protein, we prepared the Q89D mutant in a triple mutant background, V(L)-Len M4L/Y27dD/T94H, which was 4.2 kcal/mol more stable than the wild-type V(L)-Len domain. The structures of mutants V(L)-Len Q38D and V(L)-Len Q89D/M4L/Y27dD/T94H were determined by X-ray diffraction at 1.6 A resolution. We found no major perturbances in the structures of these Q-->D mutant proteins relative to structures of the parent proteins. The observed stability changes have to be accounted for by cumulative effects of the following several factors: (1) by changes in main-chain dihedral angles and in side-chain rotomers, (2) by close contacts between some atoms, and, most significantly, (3) by the unfavorable electrostatic interactions between the Asp side chain and the carbonyls of the main chain. We show that the Asn side chain, which is of similar size but neutral, is less destabilizing. The detrimental effect of Asp within a beta-sheet of an immunoglobulin-type domain can have very serious consequences. A somatic mutation of a beta-strand residue to Asp could prevent the expression of the domain both in vitro and in vivo, or it could contribute to the pathogenic potential of the protein in vivo.
About this StructureAbout this Structure
1EEU is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Factors contributing to decreased protein stability when aspartic acid residues are in beta-sheet regions., Pokkuluri PR, Gu M, Cai X, Raffen R, Stevens FJ, Schiffer M, Protein Sci. 2002 Jul;11(7):1687-94. PMID:12070321 Page seeded by OCA on Fri May 2 15:00:43 2008