Biomedical subjects

Peter D Sun

Publications and source records attributed to Peter D Sun.

21 records · Page 2Linked to original sources

PubMed2002

Crystallization and preliminary crystallographic studies of human TGF-beta type II receptor ligand-binding domain.

Three constructs (residues 15-136, 22-136 and 27-136) of the truncated extracellular domain of human transforming growth factor beta type II receptor (TBRII) were overexpressed in Escherichia coli. The constructs are referred to as TBRII(15-136), TBRII(22-136) and TBRII(27-136). The refolded receptors were purified using a combination of ion-exchange and size-exclusion chromatography. The purified receptors have an apparent molecular weight of 14 kDa as judged by size-exclusion chromatography. In the crystallization trials, TBRII(15-136) and TBRII(22-136) formed mostly crystal-like spheres but failed to produce data-quality crystals. TBRII(27-136) yielded large single crystals from hanging drops using the vapor-diffusion procedure with PEG 2000 or 4000 at pH 5.0. The crystals diffracted to 1.05 A [using the X9B beamline operated at lambda = 1.0092 A of the National Synchrotron Light Source (NSLS) at the Brookhaven National Laboratory] and belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 35.5, b = 40.7, c = 76.2 A. There was one molecule in the asymmetric unit, which corresponds to a solvent content of 42.1%.

Chromatography↗

PubMed2002

A structural perspective on MHC class I recognition by killer cell immunoglobulin-like receptors.

Killer cell immunoglobulin-like receptors (KIR) play a critical role in the regulation of natural killer (NK) cell activity through their recognition of class I MHC molecules expressed on target cells. KIR recognition provides vital information to NK cells about whether a target cell should be lysed or spared. Understanding the molecular mechanism of this recognition has remained a strong focus of investigation. This has resulted in the crystal structures of several members of the KIR family and more recently the determinations of the three dimensional structures of KIR2DL2 and KIR2DL1 complexed with their respective ligands, HLA-Cw3 and HLA-Cw4. A strong structural conservation has been revealed both in the receptor design and in the overall mode of KIR binding to class I molecules. Nevertheless, distinct differences in the receptor binding sites allow for high specificity between ligands. Furthermore, unexpected similarities with T-cell receptor (TCR) recognition of MHC molecules are also observed. The detailed interactions between KIR and HLA-C molecules and their functional implications will be reviewed here.

Amino Acid Sequence↗

PubMed2002

The 1.1 A crystal structure of human TGF-beta type II receptor ligand binding domain.

Transforming growth factor beta (TGF-beta) is involved in a wide range of biological functions including development, carcinogenesis, and immune regulation. Here we report the 1.1 A resolution crystal structure of human TGF-beta type II receptor ectodomain (TBRII). The overall structure of TBRII is similar to that of activin type II receptor ectodomain (ActRII) and bone morphogenic protein receptor type IA (BRIA). It displays a three-finger toxin fold with fingers formed by the beta strand pairs beta1-beta2, beta3-beta4, and beta5-beta6. The first finger in the TBRII is significantly longer than in ActRII and BRIA and folds tightly between the second finger and the C terminus. Surface charge distributions and hydrophobic patches predict potential TBRII binding sites.

Activin Receptors, Type I↗