PMID: 8364024
Camacho NP, Smith DR, Goldman A, Schneider B, Green D, Young PR, Berman HM
Structure of an interleukin-1 beta mutant with reduced bioactivity shows multiple subtle changes in conformation that affect protein-protein recognition.
Biochemistry. 1993 Aug 31;32(34):8749-57.
Site-specific mutagenesis was used to obtain the human interleukin-1 beta mutant protein with glycine substituted for threonine at position 9 (IL-1 beta Thr9Gly). The mutant maintains receptor binding but exhibits significantly reduced biological activity. The crystal structure of IL-1 beta Thr9Gly has been determined at 2.4-A resolution by molecular replacement techniques and refined to a crystallographic R-factor of 19.0%. IL-1 beta Thr9Gly crystallizes in a different space group (P6(5)22) than does native IL-1 beta (P4(3)); thus the molecules pack differently. Their overall structure is similar, nevertheless, with both composed of 153 amino acids which form 12 antiparallel beta-strands. However, significant conformational differences both close to and far from the site of the mutation may explain the mutant's altered properties.