Backbone dynamics of the human MIA protein studied by (15)N NMR relaxation: implications for extended interactions of SH3 domains.
The melanoma inhibitory activity (MIA) protein is a clinically valuable marker in patients with malignant melanoma as enhanced values diagnose metastatic melanoma stages III and IV. Here, we report the backbone dynamics of human MIA studied by (15)N NMR relaxation experiments. The folded core of human MIA is found to be rigid, but several loops connecting beta-sheets, such as the RT-loop for example, display increased mobility on picosecond to nanosecond time scales. One of the most important dynamic features is the pronounced flexibility of the distal loop, comprising residues Asp 68 to Ala 75, where motions on time scales up to milliseconds occur. Further, significant exchange contributions are observed for residues of the canonical binding site of SH3 domains including the RT-loop, the n-Src loop, for the loop comprising residues 13 to 19, which we refer to as the"disulfide loop", in part for the distal loop, and the carboxyl terminus of human MIA. The functional importance of this dynamic behavior is discussed with respect to the biological activity of several point mutations of human MIA. The results of this study suggest that the MIA protein and the recently identified highly homologous fibrocyte-derived protein (FDP)/MIA-like (MIAL) constitute a new family of secreted proteins that adopt an SH3 domain-like fold in solution with expanded ligand interactions.
Stoll
Raphael
R
Max Planck Institute of Biochemistry, D-82152 München, Germany.
Renner
Christian
C
Buettner
Reinhard
R
Voelter
Wolfgang
W
Bosserhoff
Anja-Katrin
AK
Holak
Tad A
TA
D000595:Amino Acid Sequence; D001665:Binding Sites; D002448:Cell Adhesion; D016326:Extracellular Matrix Proteins; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008545:Melanoma / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis; D011487:Protein Conformation; D017510:Protein Folding; D017386:Sequence Homology, Amino Acid; D014407:Tumor Cells, Cultured; D018909:src Homology Domains
D016326:Extracellular Matrix Proteins; C090059:MIA protein, human; D009363:Neoplasm Proteins