%0 Comparative Study
%T Beta-sheet secondary structure of an LDL receptor domain from complement factor I by consensus structure predictions and spectroscopy.
%A Ullman CG
%A Haris PI
%A Smith KF
%A Sim RB
%A Emery VC
%A Perkins SJ
%J FEBS Lett
%V 371
%N 2
%D Sep 1995 4
%M 7672128
%F 3.864
%R 10.1016/0014-5793(95)00916-w
%X Low density lipoprotein receptor domains (LDLrs) represent a large cell surface receptor superfamily of consensus length 39 residues. Alignment of 194 sequences indicated highly conserved Cys and Asp/Glu residues, and a consensus secondary structure with three beta-strands was predicted. Sequence threading against known protein folds indicated consistency with small beta-sheet proteins. Complement factor I contains two LDLrs, and the second of these was successfully expressed using a bacterial pGEX system. FT-IR spectroscopy on this indicated a small amount of beta-sheet together with turns and loops. LDLr is proposed to have a beta-sheet structure in which the five biologically important Asp/Glu residues are located on an exposed loop.