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1uid
From Proteopedia
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ANALYSIS OF THE STABILIZATION OF HEN LYSOZYME WITH THE HELIX DIPOLE AND CHARGED SIDE CHAINS
Overview
His 15 of hen lysozyme is located at the protein surface and is partly buried by the neighboring residues. The side chain of His 15 forms hydrogen bonds with surrounding residues and these hydrogen bonds are somewhat buried. A series of mutant lysozymes at the position 15 (Gly, Ala, Val, and Phe) was prepared, and their stabilities were analyzed by GdnHCl denaturation and X-ray crystallography. The mutants were less stable than the wild type at pH 5.5 and 35 degrees C. In H15G and H15A, X-ray crystallography revealed two fixed water molecules at the mutated region, which formed similar hydrogen bonds to those in the wild type. On the other hand, it was suggested that the hydrogen bonds were disrupted and that several unfavorable van der Waals' contacts occurred in H15V and H15F. Therefore, we concluded that His 15 stabilized the lysozyme structure by forming hydrogen bonds and the best packing with the neighboring residues. Moreover, we found that the method of protein stabilization by increasing the hydrophobicity of an amino acid residue was not always effectively applicable, especially when the residue had formed a hydrogen bond.
About this Structure
1UID is a Single protein structure of sequence from Gallus gallus. Active as Lysozyme, with EC number 3.2.1.17 Full crystallographic information is available from OCA.
Reference
Analysis of the stability of mutant lysozymes at position 15 using X-ray crystallography., Ohmura T, Ueda T, Motoshima H, Tamura T, Imoto T, J Biochem. 1997 Sep;122(3):512-7. PMID:9348077
Page seeded by OCA on Thu Feb 21 15:24:53 2008
