Resonance assignments for Oncostatin M, a 24-kDa alpha-helical protein.
Oncostatin M (OM) is a cytokine that shares a structural and functional relationship with interleukin-6, leukemia inhibitory factor, and granulocyte-colony stimulating factor, which regulate the proliferation and differentiation of a variety of cell types. A mutant version of human OM in which two N-linked glycosylation sites and an unpaired cysteine have been mutated to alanine (N76A/C81A/N193A) has been expressed and shown to be active. The triple mutant has been doubly isotope-labeled with 13C and 15N in order to utilize heteronuclear multidimensional NMR techniques for structure determination. Approximately 90% of the backbone resonances were assigned from a combination of triple-resonance data (HNCA, HNCO, CBCACONH, HBHACONH, HNHA and HCACO), intraresidue and sequential NOEs (3D 15N-NOESY-HMQC and 13C-HSQC-NOESY) and side-chain information obtained from the CCONH and HCCONH experiments. Preliminary analysis of the NOE pattern in the 15N-NOESY-HMQC spectrum and the 13C alpha secondary chemical shifts predicts a secondary structure for OM consisting of four alpha-helices with three intervening helical regions, consistent with the four-helix-bundle motif found for this cytokine family. As a 203-residue protein with a molecular weight of 24 kDa, Oncostatin M is the largest alpha-helical protein yet assigned.
Hoffman
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Immunex Corp., Seattle, WA 98101, USA.
Moy
F J
FJ
Price
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V
Richardson
J
J
Kaubisch
D
D
Frieden
E A
EA
Krakover
J D
JD
Castner
B J
BJ
King
J
J
March
C J
CJ
Powers
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R
D000595:Amino Acid Sequence; D016207:Cytokines / Q000737:chemistry* / Q000235:genetics; D006031:Glycosylation; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009154:Mutation; D053683:Oncostatin M; D010455:Peptides / Q000737:chemistry* / Q000235:genetics; D017433:Protein Structure, Secondary
D016207:Cytokines; C508351:OSM protein, human; D010455:Peptides; D053683:Oncostatin M