Structural requirements of MLD-containing disintegrins for functional interaction with alpha 4 beta 1 and alpha 9 beta1 integrins.
Three non-RGD-containing disintegrins, VLO5, EO5, and EC3, belong to the heterodimeric family of these snake venom-derived proteins. They are potent inhibitors of certain leukocyte integrins such as alpha4beta1, alpha4beta7, and alpha9beta1, and act through the MLD motif present in one of their subunits. However, the selectivity of these disintegrins to interact with integrins is related to the amino acid composition of the integrin-binding loop in the MLD-containing subunit. The most important amino acid is that preceding the MLD motif. In vitro experiments in adhesion and ELISA assays revealed that the TMLD-containing disintegrins, VLO5 and EO5, appeared to be very potent inhibitors of human alpha4beta1 and alpha9beta1 and less effective in inhibition of the alpha4beta7 integrin. The reverse effect was observed for the AMLD-containing disintegrin, EC3. The data with native disintegrins were confirmed by experiments with synthetic peptides displaying TMLD and AMLD motifs. The MLD-containing disintegrins showed differential activities to inhibit human and murine alpha4beta1 integrin. EC3 was a weaker inhibitor of human integrin, whereas VLO5 and EO5 less actively inhibited murine alpha4beta1. These data describe a useful set of potent and selective integrin antagonists and suggest conformational requirements of human and mouse integrins for interaction with ligands.
Bazan-Socha
Stanislawa
S
Department of Biology, College of Science and Technology, Temple University, Philadelphia, Pennsylvania 19122, USA.
Kisiel
Dariusz G
DG
Young
Brad
B
Theakston
R David G
RD
Calvete
Juan J
JJ
Sheppard
Dean
D
Marcinkiewicz
Cezary
C
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D045744:Cell Line, Tumor; D019281:Dimerization; D019483:Disintegrins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology; D006801:Humans; D039041:Integrin alpha4beta1 / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D016023:Integrins / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D019169:Jurkat Cells; D020014:K562 Cells; D008546:Melanoma, Experimental; D051379:Mice; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry; D010455:Peptides / Q000138:chemical synthesis / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012910:Snake Venoms / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D019483:Disintegrins; D039041:Integrin alpha4beta1; D016023:Integrins; D009842:Oligopeptides; D010455:Peptides; D012910:Snake Venoms; C113256:integrin alpha 9 beta 1; C047981:arginyl-glycyl-aspartic acid