NMR constrained solution structures for laminin peptide 11. Analogs define structural requirements for inhibition of tumor cell invasion of basement membrane matrix.
Peptide 11, CDPGYIGSR-NH2, is a segment of laminin which blocks tumor cell invasion. A high affinity laminin receptor in tumor cells is thought to be blocked by the carboxyl-terminal YIGSR, and conformational energy calculations suggest that the glycine in YIGSR allows an important conformational bend. We replaced the YIGSR glycine residue in peptide 11 with either D-alanine or L-alanine to allow or disfavor the proposed glycine bend. We found the Gly7-->D-Ala7 analog to be equal to peptide 11 in inhibiting tumor cell invasion of basement membrane matrix. The Gly7-->L-Ala7 analog was much less capable of invasion inhibition. Two-dimensional 1H-1H NMR was used to study the solution conformations of the peptide 11 analogs. NOESY experiments revealed close NH-NH contacts in peptide 11 and the D-Ala7 analog, but not in the L-Ala7 analog. Molecular dynamics generated low energy structures with excellent NOE agreement for peptide 11 and its analogs. Both peptide 11 and the D-Ala7 analog, but not the less active L-Ala7 analog, were predicted to have similar bends around Gly7 or D-Ala7. These results suggest that a bend in the YIGSR region of peptide 11 may be important for the binding of laminin to its metastasis-associated receptor.
Ostheimer
G J
GJ
Department of Chemistry, Montana State University, Bozeman 59717.
Starkey
J R
JR
Lambert
C G
CG
Helgerson
S L
SL
Dratz
E A
EA
D000595:Amino Acid Sequence; D000818:Animals; D001485:Basement Membrane / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D007797:Laminin / Q000737:chemistry / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008546:Melanoma, Experimental / Q000473:pathology*; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009361:Neoplasm Invasiveness; D009842:Oligopeptides / Q000737:chemistry* / Q000494:pharmacology*; D011487:Protein Conformation; D014407:Tumor Cells, Cultured
D007797:Laminin; D009842:Oligopeptides; C067029:cystinyl-aspartyl-prolyl-glycyl-tyrosyl-isoleucyl-glycyl-seryl-arginyl-NH2