Diabetes-associated mutations in insulin identify invariant receptor contacts.
Mutations in human insulin cause an autosomal-dominant syndrome of diabetes and fasting hyperinsulinemia. We demonstrate by residue-specific photo cross-linking that diabetes-associated mutations occur at receptor-binding sites. The studies use para-azido-phenylalanine, introduced at five sites by total protein synthesis. Because two such sites (Val(A3) and Phe(B24)) are largely buried in crystal structures of the free hormone, their participation in receptor binding is likely to require a conformational change to expose a hidden functional surface. Our results demonstrate that this surface spans both chains of the insulin molecule and includes sites of rare human mutations that cause diabetes.
Xu
Bin
B
Case Western Reserve University, Department of Biochemistry, 10900 Euclid Ave., SOM Room W427, Cleveland, OH 44106-4935, USA.
Hu
Shi-Quan
SQ
Chu
Ying-Chi
YC
Wang
Shuhua
S
Wang
Run-Ying
RY
Nakagawa
Satoe H
SH
Katsoyannis
Panayotis G
PG
Weiss
Michael A
MA
D001386:Azides; D001665:Binding Sites / Q000235:genetics; D003920:Diabetes Mellitus / Q000235:genetics*; D006801:Humans; D007328:Insulin / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D015394:Molecular Structure; D009154:Mutation; D010649:Phenylalanine / Q000031:analogs & derivatives; D011972:Receptor, Insulin / Q000378:metabolism*
D001386:Azides; D007328:Insulin; C027162:4-azidophenylalanine; D010649:Phenylalanine; D011972:Receptor, Insulin