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Design of Peptides with High Affinities for Heparin and Endothelial Cell Proteoglycans

2000; Elsevier BV; Volume: 275; Issue: 11 Linguagem: Inglês

10.1074/jbc.275.11.7701

1083-351X

Angela Verrecchio, Markus W. Germann, Barbara P. Schick, Brian Kung, T.E. Twardowski, James D. San Antonio,

Cell Adhesion Molecules Research

Proteoglycan-binding peptides were designed based on consensus sequences in heparin-binding proteins: XBBXBX and XBBBXXBX, where X and B are hydropathic and basic residues, respectively. Initial peptide constructs included (AKKARA) n and (ARKKAAKA) n ( n = 1–6). Affinity coelectrophoresis revealed that low M r peptides (600–1300) had no affinities for low M r heparin, but higher M r peptides (2000–3500) exhibited significant affinities ( K d ≅ 50–150 nm), which increased with peptide M r . Affinity was strongest when sequence arrays were contiguous and alanines and arginines occupied hydropathic and basic positions, but inclusion of prolines was disruptive. A peptide including a single consensus sequence of the serglycin proteoglycan core protein bound heparin strongly ( K d ≅ 200 nm), likely owing to dimerization through cysteine-cysteine linkages. Circular dichroism showed that high affinity heparin-binding peptides converted from a charged coil to an α-helix upon heparin addition, whereas weak heparin-binding peptides did not. Higher M r peptides exhibited high affinities for total endothelial cell proteoglycans ( K d ≅ 300 nm), and ∼4-fold weaker affinities for their free glycosaminoglycan chains. Thus, peptides including concatamers of heparin-binding consensus sequences may exhibit strong affinities for heparin and proteoglycans. Such peptides may be applicable in promoting cell-substratum adhesion or in the design of drugs targeted to proteoglycan-containing cell surfaces and extracellular matrices.