Peptide ligand

Orexin A and B (also known as hypocretins), two recently discovered neuropeptides, play an important role in food intake, sleep/wake cycle and neuroendocrine functions. Orexins are endogenous ligands of two G-protein-coupled receptors, termed OX1 and OX2. This work presents the first short orexin A and B analogues, orexin A 23–33 and orexin B 18–28, with high affinity (119 ± 49 and 49 ± 23 nM) for OX1 receptors expressed on SK-N-MC cells and indicates the importance of the C-terminal part of the orexin peptides for this ligand–receptor interaction.

8p research12 01-06-2013 35 5   Download

Soybean 4-kDa peptide, a hormone-like peptide, is a ligand for the 43-kDaprotein in legumes that functions as aprotein kinase and controls cell proliferation and differentiation. As this peptide stimulates proteinkinase activity, the interaction between the 4-kDa peptide (leginsulin) and the 43-kDa protein is considered important for signal transduction. However, the mechanism of interaction between the 4-kDa peptide and the 43-kDa protein is not clearly understood.

10p fptmusic 16-04-2013 37 3   Download

The toxicity of the pea albumin 1b (PA1b), a 37 amino-acid peptide extracted from pea seeds, for cereal weevils (Sito-philus oryzae, Sitophilus granariusandSitophilus zeamais) was recently discovered.The mechanism of action of this new entomotoxin is still unknown and potentially involves a target protein in the insect tissues.This work describes the characterization of a high-affinity binding site for PA1b in a microsomal fraction ofSitophilusspp.extracts.Purified PA1b was labeled to a high specific radioactivity (c.

7p fptmusic 16-04-2013 41 3   Download

The natriuretic peptide receptor-A (NPR-A) is composed of an extracellu-lar ligand-binding domain, a transmembrane-spanning domain, a kinase homology domain (KHD) and a guanylyl cyclase domain. Because the presence of ATP or adenylylimidodiphosphate reduces atrial natriuretic peptide (ANP) binding and is required for maximal guanylyl cyclase activ-ity, a direct interaction of ATP with the receptor KHD domain is plaus-ible.

12p fptmusic 12-04-2013 36 2   Download

Using NMR spectroscopy and simulated annealing calculations, we deter-mined the solution structure of the disulfide-linked cyclized decapeptide ACLPWSDGPC (SD), which is bound to an anti-(gibberellin A4) mAb 4-B8(8)⁄E9 and was found to be the first peptidyl mimotope for a hydro-phobic ligand. The resulting structure of the peptide showed ab-turn-like conformation in residues three to seven and the region converges well (average rmsd 0.54 A ˚ ).

11p fptmusic 12-04-2013 49 3   Download

Formyl peptide receptor-like 1 (FPRL1) is a seven transmembrane domain, G protein-coupled receptor that interacts with a variety of exogenous and host-derived agonists. In order to identify domains crucial for ligand recog-nition by FPRL1, we used chimeric receptors with segments in FPRL1 replaced by corresponding amino acid sequences derived from the proto-type formyl peptide receptor FPR. The chimeric receptors were stably transfected into human embryonic kidney epithelial cells and the capacity of the cells to migrate in response to formyl peptide receptor agonists was evaluated. ...

10p awards 05-04-2013 36 3   Download

Toovercome the difficultyof characterizing the structures of the extracellular loops (eLPs) ofGprotein-coupledreceptors (GPCRs) other than rhodopsin, we have explored a strategy to generate a three-dimensional structural model for a GPCR, the thromboxane A2 receptor. This three-dimen-sional structurewas completedby the assembly of theNMR structures of the computation-guided constrained peptides that mimicked the extracellular loops and connected to the conserved seven transmembrane domains.

11p awards 05-04-2013 41 4   Download

The platelet integrin receptoraIIbb3 plays a critical role in thrombosis and haemostasis by mediating interactions between platelets and several ligands but primarily fibrin-ogen. It has been shown previously that the YMESRADR KLAEVGRVYLFL (313–332) sequence of theaIIb subunit plays an important role in platelet activation, fibrinogen binding andaIIbb3 -mediated outside-in signalling.

8p dell39 03-04-2013 52 4   Download

The molecular chaperone Grp94 (gp96) of the endoplasmic reticulum (ER) lumen plays an essential role in the structural maturation and⁄or secretion of proteins destined for transport to the cell surface. Its proposed role in binding and transferring peptides for immune recognition is, however, controversial.

10p dell39 27-03-2013 41 3   Download

a-Conotoxins are small peptides from cone snail venoms that function as nicotinic acetylcholine receptor (nAChR)-competitive antagonists differenti-ating between nAChR subtypes. Current understanding about the mechan-ism of these selective interactions is based largely on mutational analyses, which identify amino acids in the toxin and nAChR that determine the energetics of ligand binding.

16p inspiron33 26-03-2013 47 5   Download

Synaptic targeting of GluR-A subunit-containing glutamate receptors involves an interaction with synapse-associated protein 97 (SAP97). The C-terminus of GluR-A, which contains a class I PDZ ligand motif (-x-Ser⁄Thr-x-/-COOH where /is an aliphatic amino acid) associates preferentially with the second PDZ domain of SAP97 (SAP97PDZ2).

11p inspiron33 23-03-2013 40 5   Download

Antibodies are the paradigm for binding proteins, with their hypervariable loop region supported by a structurally rigid framework, thus providing the vast repertoire of antigen-binding sites in the immune system. Lipoca-lins are another family of proteins that exhibit a binding site with high structural plasticity, which is composed of four peptide loops mounted on a stable b-barrel scaffold.

7p galaxyss3 07-03-2013 45 3   Download

Structural analysis of protein tyrosine phosphatases (PTPs) has expanded considerably in the last several years, producing more than 200 structures in this class of enzymes (from 35 different proteins and their complexes with ligands). The small–medium size of the catalytic domain of280 resi-dues plus a very compact fold makes it amenable to cloning and over-expression in bacterial systems thus facilitating crystallographic analysis.

9p media19 05-03-2013 38 2   Download

4-Aminobutyrate type A (GABAA) receptor-associated protein (GABA-RAP) is a ubiquitin-like modifier implicated in the intracellular trafficking of GABAAreceptors, and belongs to a family of proteins involved in intra-cellular vesicular transport processes, such as autophagy and intra-Golgi transport.

13p media19 04-03-2013 31 2   Download

Two structures of monomeric methionyl-tRNA synthetase, fromMycobac-terium smegmatis, in complex with the ligands methionine⁄adenosine and methionine, were analyzed by X-ray crystallography at 2.3 A˚ and at 2.8 A˚ , respectively. The structures demonstrated the flexibility of the multidomain enzyme. A new conformation of the structure was identified in which the connective peptide domain bound more closely to the catalytic domain than described previously.

16p viettel02 19-02-2013 45 3   Download

Apoptosis or programmed cell death is an inherent part of the development and homeostasis of multicellular organisms. Dysregulation of apoptosis is implicated in the pathogenesis of diseases such as cancer, neurodegenera-tive diseases and autoimmune disorders. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is able to induce apoptosis by binding death receptor (DR)4 (TRAIL-R1) and DR5 (TRAIL-R2), which makes TRAIL an interesting and promising therapeutic target.

13p mobifone23 18-01-2013 46 3   Download

Tetratricopeptide repeats (TPRs) are protein domains that mediate key protein–protein interactions in cells. Several TPR domains bind the C-ter-mini of the chaperones heat shock protein (Hsp)90 and⁄or Hsp70, and exchange of such binding partners is key for the heat shock response.

9p mobifone23 18-01-2013 29 3   Download

The mammalian natriuretic peptide system, consisting of at least three ligands and three receptors, plays critical roles in health and disease. Exam-ination of genetically engineered animal models has suggested the signifi-cance of the natriuretic peptide system in cardiovascular, renal and skeletal homeostasis.

12p cosis54 05-01-2013 49 4   Download

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học General Psychiatry cung cấp cho các bạn kiến thức về ngành y đề tài: Altered peptide ligands inhibit arthritis induced by glucose-6-phosphate isomerase peptide...

14p thulanh15 18-10-2011 33 2   Download

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học General Psychiatry cung cấp cho các bạn kiến thức về ngành y đề tài: Identification of an altered peptide ligand based on the endogenously presented, rheumatoid arthritis-associated, human cartilage glycoprotein-39(263–275) epitope: an MHC anchor variant peptide for immune modulation...

11p thulanh13 15-10-2011 56 3   Download