1C45

MUTANT HUMAN LYSOZYME WITH FOREIGN N-TERMINAL RESIDUES

Summary for 1C45

• Entry DOI: 10.2210/pdb1c45/pdb
• Descriptor: PROTEIN (LYSOZYME), SODIUM ION (3 entities in total)
• Functional Keywords: n-terminal, stability, hydrolase
• Biological source: Homo sapiens (human)
• Cellular location: Secreted: P61626
• Total number of polymer chains: 1
• Total formula weight: 14685.58

Authors

Takano, K.,Tsuchimori, K.,Yamagata, Y.,Yutani, K. (deposition date: 1999-08-03, release date: 1999-08-20, Last modification date: 2024-10-09)

Primary citation

Takano, K.,Tsuchimori, K.,Yamagata, Y.,Yutani, K.
Effect of foreign N-terminal residues on the conformational stability of human lysozyme.
Eur.J.Biochem., 266:675-682, 1999

PubMed Abstract: To minutely understand the effect of foreign N-terminal residues on the conformational stability of human lysozyme, five mutant proteins were constructed: two had Met or Ala in place of the N-terminal Lys residue (K1M and K1A, respectively), and others had one additional residue, Met, Gly or Pro, to the N-terminal Lys residue (Met(-1), Gly(-1) and Pro(-1), respectively). The thermodynamic parameters for denaturation of these mutant proteins were examined by differential scanning calorimetry and were compared with that of the wild-type protein. Three mutants with the extra residue were significantly destabilized: the changes in unfolding Gibbs energy (DeltaDeltaG) were -9.1 to -12.2 kJ.mol-1. However, the stability of two single substitutions at the N-terminal slightly decreased; the DeltaDeltaG values were only -0.5 to -2.5 kJ.mol-1. The results indicate that human lysozyme is destabilized by an expanded N-terminal residue. The crystal structural analyses of K1M, K1A and Gly(-1) revealed that the introduction of a residue at the N-terminal of human lysozyme caused the destruction of hydrogen bond networks with ordered water molecules, resulting in the destabilization of the protein.

PubMed: 10561612
DOI: 10.1046/j.1432-1327.1999.00918.x

Experimental method

X-RAY DIFFRACTION (1.8 Å)