Structural determinants of the ADAM inhibition by TIMP-3: crystal structure of the TACE-N-TIMP-3 complex.
TIMP-3 (tissue inhibitor of metalloproteinases 3) is unique among the TIMP inhibitors, in that it effectively inhibits the TNF-alpha converting enzyme (TACE). In order to understand this selective capability of inhibition, we crystallized the complex formed by the catalytic domain of recombinant human TACE and the N-terminal domain of TIMP-3 (N-TIMP-3), and determined its molecular structure with X-ray data to 2.3 A resolution. The structure reveals that TIMP-3 exhibits a fold similar to those of TIMP-1 and TIMP-2, and interacts through its functional binding edge, which consists of the N-terminal segment and other loops, with the active-site cleft of TACE in a manner similar to that of matrix metalloproteinases (MMPs). Therefore, the mechanism of TIMP-3 binding toward TACE is not fundamentally different from that previously elucidated for the MMPs. The Phe34 phenyl side chain situated at the tip of the relatively short sA-sB loop of TIMP-3 extends into a unique hydrophobic groove of the TACE surface, and two Leu residues in the adjacent sC-connector and sE-sF loops are tightly packed in the interface allowing favourable interactions, in agreement with predictions obtained by systematic mutations by Gillian Murphy's group. The combination of favourable functional epitopes together with a considerable flexibility renders TIMP-3 an efficient TACE inhibitor. This structure might provide means to design more efficient TIMP inhibitors of TACE.
Wisniewska
Magdalena
M
Max-Planck-Institut für Biochemie, Proteinase Research Group, Am Klopferspitz 18, D-82152 Martinsried, Germany.
Goettig
Peter
P
Maskos
Klaus
K
Belouski
Edward
E
Winters
Dwight
D
Hecht
Randy
R
Black
Roy
R
Bode
Wolfram
W
D051722:ADAM Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry*; D000072198:ADAM17 Protein; D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D019717:Tissue Inhibitor of Metalloproteinase-3 / Q000737:chemistry* / Q000378:metabolism*
C088390:TIMP3 protein, human; D019717:Tissue Inhibitor of Metalloproteinase-3; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human