Exploiting the right side of the Ramachandran plot: substitution of glycines by D-alanine can significantly increase protein stability.
A major goal of protein engineering is the enhancement of protein stability. Here we demonstrate a rational method for enhancing the stability of globular proteins by targeting glycine residues which adopt conformations with Phi > 0. Replacement of such a glycine by d-alanine can lead to a significant increase in stability. The approach is tested at three sites in two model proteins. NMR and CD indicated that the substitutions do not alter the structure. Replacement of glycine-24 of the N-terminal domain of L9 (NTL9) with d-Ala results in an increase in stability of 1.3 kcal mol-1, while replacement of glycine-34 of NTL9 leads to an increase of 1.9 kcal mol-1. Replacement of glycine-331 of the UBA domain with d-Ala leads to an increase in stability of 0.6 kcal mol-1.
Anil
Burcu
B
Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794, USA.
Song
Benben
B
Tang
Yuefeng
Y
Raleigh
Daniel P
DP
D000409:Alanine / Q000737:chemistry*; D019943:Amino Acid Substitution; D005998:Glycine / Q000737:chemistry*; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D012269:Ribosomal Proteins / Q000737:chemistry*; D013329:Structure-Activity Relationship; D013816:Thermodynamics
D012269:Ribosomal Proteins; C049650:ribosomal protein L9; D000409:Alanine; D005998:Glycine