Dataset Information

Effects of the Arg-Pro and Gly-Gly-Nle Moieties on Melanocortin-1 Receptor Binding Affinities of α-MSH Peptides.

ABSTRACT: The purpose of this study was to examine the effects of the -Arg-Pro-(RP) and -Gly-Gly-Nle- (GGNle) moieties on the melanoma targeting and clearance properties of 99mTc-peptides. We synthesized four new peptides {Ac-GGNle-CCEHdFRWC-NH2, Ac-GGNle-CCEHdFRWCRP-NH2, Ac-CCEHdFRWC-NleGG-NH2 and Ac-CCEHdFRWCRP-NleGG-NH2} and determined their melanocortin-1 (MC1) receptor binding affinities in B16/F1 melanoma cells. Then we further examined the biodistribution properties of 99mTc-Ac-GGNle-CCEHdFRWCRP-NH2 and 99mTc-Ac-CCEHdFRWCRP-NleGG-NH2 in B16/F1 melanoma-bearing C57 mice. Overall, the Arg-Pro motif was critical for retaining low nanomolar MC1 receptor binding affinity. The deletion of the -RP- moiety dramatically reduced the receptor binding affinities of the peptides. The N-terminus was a better position than C-terminus for the -GGNle- moiety in retaining the lower renal and liver uptake. High melanoma uptake coupled with fast urinary clearance of 99mTc-Ac-GGNle-CCEHdFRWCRP-NH2 provided a new insight into the design of new α-melanocyte stimulating hormone (α-MSH) peptides.

SUBMITTER: Yang J

PROVIDER: S-EPMC3859464 | biostudies-literature | 2013 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Effects of the Arg-Pro and Gly-Gly-Nle Moieties on Melanocortin-1 Receptor Binding Affinities of α-MSH Peptides.

Yang Jianquan J Liu Liqin L Miao Yubin Y

ACS medicinal chemistry letters 20131001 10

The purpose of this study was to examine the effects of the -Arg-Pro-(RP) and -Gly-Gly-Nle- (GGNle) moieties on the melanoma targeting and clearance properties of 99mTc-peptides. We synthesized four new peptides {Ac-GGNle-CCEHdFRWC-NH2, Ac-GGNle-CCEHdFRWCRP-NH2, Ac-CCEHdFRWC-NleGG-NH2 and Ac-CCEHdFRWCRP-NleGG-NH2} and determined their melanocortin-1 (MC1) receptor binding affinities in B16/F1 melanoma cells. Then we further examined the biod ...[more]

PMID: 24349641

Similar Datasets

Project description:N(G)-Methylation of arginine residues in many nucleic-acid-binding proteins are formed post-translationally, catalysed by S-adenosylmethionine:protein-arginine N-methyltransferase in their glycine-rich and arginine-rich motifs. The amino acid sequences of the stimulator of HIV-1 TAR (Tat-responsive element) RNA-binding protein (SRB) and fibronectin also show the presence of the internal -Gly-Arg-Gly- (-GRG-) sequence, which is potentially methylatable by the methyltransferase. To investigate the sequence requirement for methylation of these proteins, several synthetic oligopeptides with different chain lengths and sequences similar to the -GRG- regions of SRB and fibronectin were synthesized. Whereas the heptapeptide AGGRGKG (residues 16-22 in SRB) served as the methyl acceptor for the methyltransferase with a K(m) of 50 microM, the 19-mer peptide (residues 10-28 in SRB) was methylated with a K(m) of 8.3 microM, indicating that a greater peptide chain length yields a better methyl acceptor. Product analysis of the methylated [methyl-(14)C]SRB-peptide by HPLC indicated the formation of N(G)-monomethylarginine and N(G),N(G)-dimethyl(asymmetric)arginine. Synthetic peptides containing the cell attachment sequence [Arg-Gly-Asp ('RGD')] in fibronectin, GRGDSPK, GGRGDSPK and GGGRGDSPK, were also studied; whereas GRGDSPK was a poor methyl acceptor, the longer peptides were better methyl acceptors. To provide an understanding of the effect of methylation on fibronectin peptide, arginine-unmethylated and methylated GGRGDSPK were compared for their effect on the mitogenesis induced by beta-hexosaminidase A and an agonistic antibody (mAb(15)) in bovine tracheal smooth-muscle cells; whereas the former inhibited 35-67% of mitogenesis at a concentration of 5-10 microM, the latter did not block mitogenesis. This lack of inhibition by the insertion of a methyl group on the arginyl residue of the cell attachment sequence might be due to the hindrance of the binding of fibronectin peptide to integrins.

Project description:BackgroundIntegrin-mediated interaction of neuronal cells with extracellular matrix (ECM) is important for the control of cell adhesion, morphology, motility, and differentiation in both in vitro and in vivo systems. Arg-Gly-Asp (RGD) sequence is one of the most potent integrin-binding ligand found in many native ECM proteins. An elastin-mimetic recombinant protein, TGPG[VGRGD(VGVPG)6]20WPC, referred to as [RGD-V6]20, contains multiple RGD motifs to bind cell-surface integrins. This study aimed to investigate how surface-adsorbed recombinant protein can be used to modulate the behaviors and differentiation of neuronal cells in vitro. For this purpose, biomimetic ECM surfaces were prepared by isothermal adsorption of [RGD-V6]20 onto the tissue culture polystyrene (TCPS), and the effects of protein-coated surfaces on neuronal cell adhesion, spreading, migration, and differentiation were quantitatively measured using N2a neuroblastoma cells.ResultsThe [RGD-V6]20 was expressed in E. coli and purified by thermally-induced phase transition. N2a cell attachment to either [RGD-V6]20 or fibronectin followed hyperbolic binding kinetics saturating around 2 μM protein concentration. The apparent maximum cell binding to [RGD-V6]20 was approximately 96% of fibronectin, with half-maximal adhesion on [RGD-V6]20 and fibronectin occurring at a coating concentration of 2.4 × 10-7 and 1.4 × 10-7 M, respectively. The percentage of spreading cells was in the following order of proteins: fibronectin (84.3% ± 6.9%) > [RGD-V6]20 (42.9% ± 6.5%) > [V7]20 (15.5% ± 3.2%) > TCPS (less than 10%). The migration speed of N2a cells on [RGD-V6]20 was similar to that of cells on fibronectin. The expression of neuronal marker proteins Tuj1, MAP2, and GFAP was approximately 1.5-fold up-regulated by [RGD-V6]20 relative to TCPS. Moreover, by the presence of both [RGD-V6]20 and RA, the expression levels of NSE, TuJ1, NF68, MAP2, and GFAP were significantly elevated.ConclusionWe have shown that an elastin-mimetic protein consisting of alternating tropoelastin structural domains and cell-binding RGD motifs is able to stimulate neuronal cell behaviors and differentiation. In particular, adhesion-induced neural differentiation is highly desirable for neural development and nerve repair. In this context, our data emphasize that the combination of biomimetically engineered recombinant protein and isothermal adsorption approach allows for the facile preparation of bioactive matrix or coating for neural tissue regeneration.

Dataset Information

Effects of the Arg-Pro and Gly-Gly-Nle Moieties on Melanocortin-1 Receptor Binding Affinities of α-MSH Peptides.

Publications

Effects of the Arg-Pro and Gly-Gly-Nle Moieties on Melanocortin-1 Receptor Binding Affinities of α-MSH Peptides.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets