1fkv
From Proteopedia
(New page: 200px<br /><applet load="1fkv" size="450" color="white" frame="true" align="right" spinBox="true" caption="1fkv, resolution 2.0Å" /> '''RECOMBINANT GOAT ALPH...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:1fkv.gif|left|200px]]<br /><applet load="1fkv" size=" | + | [[Image:1fkv.gif|left|200px]]<br /><applet load="1fkv" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1fkv, resolution 2.0Å" /> | caption="1fkv, resolution 2.0Å" /> | ||
'''RECOMBINANT GOAT ALPHA-LACTALBUMIN T29I'''<br /> | '''RECOMBINANT GOAT ALPHA-LACTALBUMIN T29I'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The Thr29 residue in the hydrophobic core of goat alpha-lactalbumin | + | The Thr29 residue in the hydrophobic core of goat alpha-lactalbumin (alpha-LA) was substituted with Val (Thr29Val) and Ile (Thr29Ile) to investigate the contribution of Thr29 to the thermodynamic stability of the protein. We carried out protein stability measurements, X-ray crystallographic analyses, and free energy calculations based on molecular dynamics simulation. The equilibrium unfolding transitions induced by guanidine hydrochloride demonstrated that the Thr29Val and Thr29Ile mutants were, respectively, 1.9 and 3.2 kcal/mol more stable than the wild-type protein (WT). The overall structures of the mutants were almost identical to that of WT, in spite of the disruption of the hydrogen bonding between the side-chain O-H group of Thr29 and the main-chain C=O group of Glu25. To analyze the stabilization mechanism of the mutants, we performed free energy calculations. The calculated free energy differences were in good agreement with the experimental values. The stabilization of the mutants was mainly caused by solvation loss in the denatured state. Furthermore, the O-H group of Thr29 favorably interacts with the C=O group of Glu25 to form hydrogen bonds and, simultaneously, unfavorably interacts electrostatically with the main-chain C=O group of Thr29. The difference in the free energy profile of the unfolding path between WT and the Thr29Ile mutant is discussed in light of our experimental and theoretical results. |
==About this Structure== | ==About this Structure== | ||
| - | 1FKV is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Capra_hircus Capra hircus] with CA as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Lactose_synthase Lactose synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.22 2.4.1.22] Full crystallographic information is available from [http:// | + | 1FKV is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Capra_hircus Capra hircus] with <scene name='pdbligand=CA:'>CA</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Lactose_synthase Lactose synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.22 2.4.1.22] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1FKV OCA]. |
==Reference== | ==Reference== | ||
| Line 23: | Line 23: | ||
[[Category: lactose synthase component]] | [[Category: lactose synthase component]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:39:46 2008'' |
Revision as of 10:39, 21 February 2008
|
RECOMBINANT GOAT ALPHA-LACTALBUMIN T29I
Overview
The Thr29 residue in the hydrophobic core of goat alpha-lactalbumin (alpha-LA) was substituted with Val (Thr29Val) and Ile (Thr29Ile) to investigate the contribution of Thr29 to the thermodynamic stability of the protein. We carried out protein stability measurements, X-ray crystallographic analyses, and free energy calculations based on molecular dynamics simulation. The equilibrium unfolding transitions induced by guanidine hydrochloride demonstrated that the Thr29Val and Thr29Ile mutants were, respectively, 1.9 and 3.2 kcal/mol more stable than the wild-type protein (WT). The overall structures of the mutants were almost identical to that of WT, in spite of the disruption of the hydrogen bonding between the side-chain O-H group of Thr29 and the main-chain C=O group of Glu25. To analyze the stabilization mechanism of the mutants, we performed free energy calculations. The calculated free energy differences were in good agreement with the experimental values. The stabilization of the mutants was mainly caused by solvation loss in the denatured state. Furthermore, the O-H group of Thr29 favorably interacts with the C=O group of Glu25 to form hydrogen bonds and, simultaneously, unfavorably interacts electrostatically with the main-chain C=O group of Thr29. The difference in the free energy profile of the unfolding path between WT and the Thr29Ile mutant is discussed in light of our experimental and theoretical results.
About this Structure
1FKV is a Single protein structure of sequence from Capra hircus with as ligand. Active as Lactose synthase, with EC number 2.4.1.22 Full crystallographic information is available from OCA.
Reference
Contribution of Thr29 to the thermodynamic stability of goat alpha-lactalbumin as determined by experimental and theoretical approaches., Horii K, Saito M, Yoda T, Tsumoto K, Matsushima M, Kuwajima K, Kumagai I, Proteins. 2001 Oct 1;45(1):16-29. PMID:11536356
Page seeded by OCA on Thu Feb 21 12:39:46 2008
