The RGD sequence is identified by half of the 24 known integrins, whereas alternative short peptide sequences are identified by other integrins [4]

The RGD sequence is identified by half of the 24 known integrins, whereas alternative short peptide sequences are identified by other integrins [4]. 15N with error (A). 15N with error (B).1H-15N steady-state NOE with error (C) These experiments were attained using 700 MHz NMR.(TIF) pone.0028833.s004.tif (1.5M) GUID:?92C91C08-D3E6-4B8A-9FBE-DB4F57BE737E Number S5: Assessment of model-free parameters of Rho (?) and its P48A mutant (). Generalized order parameters S2, relaxation parameter for Rho residues R49 and D51 were 39% and 54% higher than those of the P48A mutant, which caused variations in S2, Rex, and e. The S2 ideals of the P48A mutant residues R49, G50, and D51 were 29%, 14%, and 28% lower than those of Rho. The Rex ideals of Rho residues R49 and D51 were 0.91 s?1 and 1.42 s?1; however, no Rex was found for those of the P48A mutant. The e ideals of Rho residues R49 and D51 were 9.5 and 5.1 times lower than those of P48A mutant. Mutational study showed that integrin 51 prefers its ligands to consist of (G/A)RGD but not PRGD sequences for binding. These results demonstrate the N-terminal proline residue adjacent to the RGD motif impact its function and dynamics, which suggests the dynamic properties of the RGD motif may be important in Rho’s connection with integrin 51. Intro The tripeptide sequence Arg-Gly-Asp (RGD) is the consensus sequence of many adhesive proteins, such as fibronectin, fibrinogen, vitronectin, and von Willebrand element [1], [2], [3]. In mammals, 18 and 8 subunits assemble into 24 integrins. The RGD sequence is identified by half of the 24 known integrins, whereas alternate short peptide sequences are identified by additional integrins [4]. In addition to adhesive proteins, the RGD sequence is found in many proteins, including dendroaspin [5], decorsin [6], savignygrin [7], streptopain [8], -bungarotoxin [9], human being herpesvirus 8 envelope glycoprotein B [10], and disintegrins [11]. Disintegrins are the peptides found in snake venoms of the viper family and primarily inhibit the functions of 1- and 3-connected integrins. They were first identified as inhibitors of integrin IIb3 and were subsequently shown to bind with high affinity to additional integrins and to block the connection of integrins with RGD-containing proteins. They contain 47C84 amino acids with 4C7 disulfide bonds. The RGD or KGD sequences GSK-LSD1 dihydrochloride with this disintegrin family are the most important in realizing the integrin IIb3 [12], [13], GSK-LSD1 dihydrochloride [14], [15], [16]. Analyses of 3D disintegrin constructions display that they consist of a series of tightly Rabbit polyclonal to SORL1 packed loops and becomes held collectively by disulfide bonds [17], [18], [19], [20], [21]. The RGD motif is located in the apex of a 5C11 residue loop, between two strands of the protein, protruding 10C17 ? from your protein core [13]. The R and D sidechains inside a flexible loop do not interact but nearly oppose each other by 180. Many studies have shown the residues flanking the RGD motif of RGD-containing proteins impact their binding specificities and affinities on integrins [7], [10], [22], [23], [24], [25]. For example, disintegrins with an ARGDW sequence have a higher affinity for binding with the integrin IIb3, whereas disintegrins with an ARGDN sequence preferentially bind with integrins v3 and 51 [24]. The amino acid sequences of the RGD loop from RIPRGDMP to TAVRGDGP of rhodostomin (Rho), resulting in a 196-fold decrease in inhibiting integrin IIb3 [9]. Alternative of GSK-LSD1 dihydrochloride the N-terminal alanine with the proline of the RGD motif of elagantin, a disintegrin with an ARGDMP sequence, diminishes its binding to integrin 51 [25], which suggests that replacing the N-terminal proline with the alanine of the RGD motif may increase its binding to integrin 51. Consequently, it is of interest to study the effect of the N-terminal proline or alanine residue adjacent to the RGD motif within the function, structure, and dynamic associations of disintegrin. In this study, we used Rho as the model protein to investigate the effect of the N-terminal proline residue adjacent to the RGD motif within the dynamics of disintegrin and the structure-activity associations of RGD-containing proteins. Rho is definitely from venom and belongs to the family of disintegrins [26], [27], [28]. It consists of 68 amino acids, including 12 residues of cysteine and a PRGDMP sequence at positions 48C53. We previously showed that Rho indicated in (has the same function and structure as native protein [28]. In the present study, we indicated Rho P48A mutants and identified their activities in inhibiting the integrins IIb3, v3, and 51. We also used nuclear magnetic resonance (NMR) spectroscopy to compare 3D constructions and backbone dynamics. Materials and Methods Manifestation of Rho and its Mutants in P. pastoris and Purification The manifestation of Rho and eleven mutants (P48A, M52W, P48A/M52W, M52N, P48A/M52N, M52G/P53W, P48A/M52G/P53W,.