PMID- 11455596
OWN - NLM
STAT- MEDLINE
DCOM- 20010816
LR  - 20131121
IS  - 0887-3585 (Print)
IS  - 0887-3585 (Linking)
VI  - 44
IP  - 3
DP  - 2001 Aug 15
TI  - Role of non-glycine residues in left-handed helical conformation for the
      conformational stability of human lysozyme.
PG  - 233-43
AB  - 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.
FAU - Takano, K
AU  - Takano K
AD  - Institute for Protein Research, Osaka University, Yamadaoka, Suita, Osaka, Japan.
FAU - Yamagata, Y
AU  - Yamagata Y
FAU - Yutani, K
AU  - Yutani K
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Proteins
JT  - Proteins
JID - 8700181
RN  - EC 3.2.1.17 (Muramidase)
RN  - TE7660XO1C (Glycine)
SB  - IM
MH  - Amino Acid Substitution
MH  - Calorimetry
MH  - Calorimetry, Differential Scanning
MH  - Crystallography, X-Ray
MH  - Enzyme Stability
MH  - Glycine/genetics
MH  - Humans
MH  - Models, Molecular
MH  - Muramidase/*chemistry/genetics
MH  - Mutation
MH  - Protein Structure, Secondary
EDAT- 2001/07/17 10:00
MHDA- 2001/08/17 10:01
CRDT- 2001/07/17 10:00
PHST- 2001/07/17 10:00 [pubmed]
PHST- 2001/08/17 10:01 [medline]
PHST- 2001/07/17 10:00 [entrez]
AID - 10.1002/prot.1088 [pii]
PST - ppublish
SO  - Proteins. 2001 Aug 15;44(3):233-43.