1H assignment and secondary structure determination of human melanoma growth stimulating activity (MGSA) by NMR spectroscopy

Abstract
The solution structure of melanoma growth stimulating activity (MGSA) has been investigated using proton NMR spectroscopy. Sequential resonance assignments have been carried out, and elements of secondary structure have been identified on the basis of NOE, coupling constant, chemical shift, and amide proton exchange data. Long‐range NOEs have established that MGSA is a dimer in solution. The secondary structure and dimer interface of MGSA appear to be similar to those found previously for the homologous chemokine interleukin‐8 [Clore et al. (1990) Biochemistry 29, 1689‐1696]. The MGSA monomer contains a three stranded anti‐parallel β‐sheet arranged in a ‘Greek‐key’ conformation, and a C‐terininal α‐helix (residues 58 69).