1BLK

NMR ENSEMBLE OF BLK SH2 DOMAIN USING CHEMICAL SHIFT REFINEMENT, 20 STRUCTURES

1BLK の概要

• エントリーDOI: 10.2210/pdb1blk/pdb
• 分子名称: P55 BLK PROTEIN TYROSINE KINASE (1 entity in total)
• 機能のキーワード: signal transduction, tyrosine kinase, transferase, phosphotransferase, phosphorylation
• 由来する生物種: Mus musculus (house mouse)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 12750.65

構造登録者

Metzler, W.J.,Leiting, B.,Pryor, K.,Mueller, L.,Farmer II, B.T. (登録日: 1996-03-26, 公開日: 1997-03-12, 最終更新日: 2024-05-22)

主引用文献

Metzler, W.J.,Leiting, B.,Pryor, K.,Mueller, L.,Farmer 2nd., B.T.
The three-dimensional solution structure of the SH2 domain from p55blk kinase.
Biochemistry, 35:6201-6211, 1996

PubMed Abstract: Signal transduction in B cells is mediated, in part, by the interaction of the cytoplasmic components of the antigen receptor complex and various members of the src family tyrosine kinases. Key to this process appears to be the interaction of the tyrosine kinase SH2 domains with the tyrosine-phosphorylated cytoplasmic domain of Ig-alpha, a disulfide-bonded heterodimeric (with Ig-beta or Ig-gamma) transmembrane protein that noncovalently associates with the antigen receptor immunoglobin chains. In addition to binding to the phosphorylated cytoplasmic domains of Ig-alpha and Ig-beta, blk and fyn(T), two members of the src family kinases, have been shown to bind overlapping but distinct sets of phosphoproteins [Malek & Desiderio (1993) J. Biol. Chem. 268. 22557-22565]. A comparison of their three-dimensional structures may elucidate the apparently subtle differences required for phosphoprotein discrimination. To begin characterizing the blk/fyn/phosphosphoprotein interactions, we have determined the three-dimensional solution structure of the SH2 domain of blk kinase by nuclear magnetic resonance (NMR) spectroscopy. 1H, 13C, and 15N resonances of the SH2 domain of blk kinase were assigned by analysis of multidimensional, double- and triple-resonance NMR experiments. Twenty structures of the blk SH2 domain were refined with the program X-PLOR using a total of 2080 experimentally derived conformational restraints. The structures converged to a root-mean-squared (rms) distance deviation of 0.51 and 0.95 A for the backbone atoms and for the non-hydrogen atoms, respectively. The blk SH2 domain adopts the prototypical SH2 fold. Structurally, blk SH2 is most similar to the crystal structure of the v-src SH2 domain [Waksman et al. (1993) Nature 358.646-653] and superimposes on the crystal structure with an rmsd of 1.52 A for the backbone atoms. The largest deviations occur in the four loops interconnecting beta-strands A-E, which are the least well-defined regions in the NMR structure. Exclusion of these loops lowers this rmsd to 0.82 A. The conformation of the BC loop in the blk SH2 domain is similar to the open conformation in the apo lck SH2 domain, suggesting that, like the lck SH2 domain, the blk SH2 domain may have a gated phosphopeptide binding site. Finally, it is proposed that the amino acid substitution of Lys 88 (blk) for Glu [fyn(T)] is important for the observed differences in specificity between blk and fyn(T) SH2 domains.

PubMed: 8639560
DOI: 10.1021/bi960157x

実験手法

SOLUTION NMR