NMR solution structure of the angiostatic peptide anginex

Abstract

Anginex, a designed peptide 33mer, is known to function both as an antiangiogenic and bactericidal agent. Solving the NMR solution structure of the peptide is key to understand better its structureactivity relationships and to design more bioactive peptides and peptide mimetics. However, structure elucidation of anginex has been elusive due to subunit exchange-induced resonance broadening. Here, we found that performing NMR structural studies in a micellar environment abolishes exchange broadening and allows the structure of anginex to be determined. Anginex folds in an amphipathic, three-stranded antiparallel β-sheet conformation with functionally key hydrophobic residues lying on one face of the β-sheet and positively charged, mostly lysine residues, lying on the opposite face. Structural comparison is made with a homologous, yet relatively inactive peptide, βpep-28. These results contribute to the design of peptidomimetics of anginex for therapeutic use against angiogenically-related diseases like cancer, as well as infectious diseases.

Ovarian tumor growth regression using a combination of vascular targeting agents anginex or topomimetic 0118 and the chemotherapeutic irofulven

“…Having established anginex as a potent antiangiogenic and antitumor agent, we used the folded structure of anginex [28,29] to design a small library of calix [4]arene-scaffold protein surface topomimetics that embodied the molecular dimensions, surface topology, and overall chemical composition of the peptide. From screening of this library, we demonstrated that topomimetic 0118 was also a potent angiogenesis inhibitor in vitro, as well as in vivo [30].…”

Structure-Based Optimization of Angiostatic Agent 6DBF7, an Allosteric Antagonist of Galectin-1

“…6DBF7, which is about onethird the mass of anginex, was shown to inhibit tumor growth in mice better than parent anginex. Although both anginex and 6DBF7 share the same spatial arrangements of functionally important amino acid residues in the context of antiparallel b-sheet structure (Dings et al, 2003a;Mayo et al, 2003;Arroyo and Mayo, 2007), it was unknown whether 6DBF7 targeted gal-1 similar to anginex. The previous results demonstrate that the DBF-based peptidomimetic indeed targets gal-1.…”

Molecular mimicry of conformationally diverse β-sheets by using α/β-peptide foldamers

“…148 High resolution structure of anginex was determined at 1 mM peptide concentration in a H2O:DMSO 1:1 mixture, pH 5.5 and 40˘C after addition of 50 mM DPC. 110 In our hand, these conditions did not result in reasonable spectra.…”

“…We found values around zero for the first strand indicating random conformation in line with the earlier observation that the first strand of the -sheet was more flexible than the other two. 110 Generally, SSP values were lower than that of the parent peptide, all  3 substitutions resulted in induced helical propensity in the first strand, which could be explained by the helix promoting tendencies of these building blocks and the flexibility of this segment. These suggested that the amino acid replacements had a strong effect on the secondary structure propensity of an entire chain segment.…”

“…110. This procedure involved manual model construction and initial folding into the proposed β-sheet, then 10 ns molecular dynamics simulation was run with the literature NOE distance restraints.…”