| AVS 54th International Symposium | |
| Biomaterial Interfaces | Tuesday Sessions |
| Session BI-TuM |
| Session: | Proteins at Interfaces |
| Presenter: | S.R. Cohen, Weizmann Institute of Science, Israel |
| Authors: | G. Rosenblum, Weizmann Institute of Science, Israel S.R. Cohen, Weizmann Institute of Science, Israel J. Frenkel, Weizmann Institute of Science, Israel N. Slack, Veeco Metrology Division, Santa Barbara I. Sagi, Weizmann Institute of Science, Israel |
| Correspondent: | Click to Email |
The multi-domain enzyme pro-matrix metaloproteinase-9 (pro-MMP-9) is recognized as playing a key role in tumor biology, autoimmune diseases, and vascular pathology. This enzyme cannot be crystallized and hence the only structural information available is of the two isolated terminal domains. Until now, structure of the vital linker domain that connects these terminal domains was unknown. A lack of reliable means to bind the protein to the surface has plagued previous structural characterization by high-resolution AFM imaging. In order to obtain high-quality AFM images of the small protein, novel amine-modified surfaces were employed to immobilize the protein during the extensive rinsing required for removing features due to buffer salts. AFM images presented in this work provide the first definitive confirmation of the multi-domain structure, wherein two terminal domains are connected by a linker segment. Parallel analysis of a mutant lacking the linker showed a less extant shape. Statistical analysis of the AFM images revealed differences in both heights and lengths between the native and mutant proteins, and provided evidence that the linker imparts significant conformational freedom to the molecule, which is likely important in its biological functioning. Biological functioning was further probed, by examining interaction of the enzyme with collagen. Molecular modeling based on the SAXS data provides complementary supporting data.