Structure and potential C-terminal dimerization of a recombinant mutant of surfactant-associated protein C in chloroform/methanol.
The solution structure of a recombinant mutant [rSP-C (FFI)] of the human surfactant-associated protein C (hSP-C) in a mixture of chloroform and methanol was determined by high-resolution NMR spectroscopy. rSP-C (FFI) contains a helix from Phe5 to the C-terminal Leu34 and is thus longer by two residues than the helix of porcine SP-C (pSP-C), which is reported to start at Val7 in the same solvent. Two sets of resonances at the C-terminus of the peptide were observed, which are explained by low-order oligomerization, probably dimerization of rSP-C (FFI) in its alpha-helical form. The dimerization may be induced by hydrogen bonding of the C-terminal carboxylic groups or by the strictly conserved C-terminal heptapeptide segment with a motif similar to the GxxxG dimerization motif of glycophorin A. Dimerization at the heptapeptide segment would be consistent with findings based on electrospray ionization MS data, chemical cross-linking studies, and CNBr cleavage data.
Luy
Burkhard
B
Institut für Organische Chemie und Biochemie, Technische Universität München, Garching, Germany.
Diener
Alexander
A
Hummel
Rolf-Peter
RP
Sturm
Ernst
E
Ulrich
Wolf-Rüdiger
WR
Griesinger
Christian
C
D020816:Amino Acid Motifs; D000818:Animals; D002725:Chloroform / Q000737:chemistry; D019281:Dimerization; D006801:Humans; D000432:Methanol / Q000737:chemistry; D008958:Models, Molecular; D009154:Mutation; D019906:Nuclear Magnetic Resonance, Biomolecular; D037721:Pulmonary Surfactant-Associated Protein C / Q000737:chemistry* / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry; D013552:Swine
D037721:Pulmonary Surfactant-Associated Protein C; D011994:Recombinant Proteins; D002725:Chloroform; D000432:Methanol