PDBsum entry 1ge0

Hydrolase

PDB id: 1ge0

Contents

Protein chain

130 a.a. *

Metals

_NA

Waters ×263

* Residue conservation analysis

PDB id:

1ge0

Name:

Hydrolase

Title:

Crystal structure of mutant human lysozyme substituted at left-handed helical positions

Structure:

LysozymE C. Chain: a. Engineered: yes. Mutation: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Expressed in: saccharomyces cerevisiae. Expression_system_taxid: 4932.

Resolution:

1.80Å R-factor: 0.180

Authors:

K.Takano,Y.Yamagata,K.Yutani

Key ref:

K.Takano et al. (2001). Role of non-glycine residues in left-handed helical conformation for the conformational stability of human lysozyme. Proteins, 44, 233-243. PubMed id: 11455596 DOI: 10.1002/prot.1088

Date:

06-Oct-00 Release date: 08-Nov-00

Protein chain

P61626  (LYSC_HUMAN) -  Lysozyme C from Homo sapiens

Seq: 148 a.a.

Struc: 130 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.3.2.1.17 - lysozyme.
• Reaction: Hydrolysis of the 1,4-beta-linkages between N-acetyl-D-glucosamine and N-acetylmuramic acid in peptidoglycan heteropolymers of the prokaryotes cell walls.

DOI no: 10.1002/prot.1088

Proteins 44:233-243 (2001)

PubMed id: 11455596

Role of non-glycine residues in left-handed helical conformation for the conformational stability of human lysozyme.

K.Takano, Y.Yamagata, K.Yutani.

ABSTRACT

To understand the role of non-Gly residues in the left-handed helical conformation for the conformational stability of a protein, the non-Gly to Gly and Ala mutations at six left-handed residues (R21, Y38, R50, Q58, H78, and N118) of the human lysozyme were examined. The thermodynamic parameters for denaturation were determined using a differential scanning calorimeter, and the crystal structures were analyzed by X-ray crystallography. If a left-handed non-Gly had an unfavorable steric interaction between the side-chain Cbeta and backbone, the Gly mutation would be expected to stabilize more than the Ala mutation at the same position. For the mutant human lysozymes, however, there were few differences in the denaturation Gibbs energy (DeltaG) between the Gly and Ala mutants, except for the substitution at position 58. Analysis of the changes in stability (DeltaDeltaG) based on the structures of the wild-type and mutant proteins showed that the experimental DeltaDeltaG value of Q58G was approximately 7 kJ/mol higher than the estimated value without consideration of any local steric interaction. These results indicate that only Q58G increased the stability by elimination of local constraints. The residue 58 is located at the most rigid position in the left-handed non-Gly residues and is involved in its enzymatic function. It can be concluded that the left-handed non-Gly residues do not always have unfavorable strain energies as compared with Gly at the same position.

Selected figure(s)

Figure 3.
Figure 3. Stereodrawings of the structures in the vicinity of the mutation sites for (a) Q58G, Q58A, and wild-type; (b) H78G, H78A, and wild-type; and (c) N118G, N118A, and wild-type human lysozymes. Wild-type and mutant structures are superimposed.

Figure 5.
Figure 5. Structures in the vicinity of mutation sites for position 21 (a) wild-type, (b) R21G, and (c) R21A human lysozymes. Thin lines and filled circles represent hydrogen bonds and water molecules, respectively.

The above figures are reprinted by permission from John Wiley & Sons, Inc.: Proteins (2001, 44, 233-243) copyright 2001.

Figures were selected by an automated process.