Reference "Solution structure and lipid binding of a nonspecific lipid transfer protein extracted from maize seeds"

Reference ID

7277

Title

Solution structure and lipid binding of a nonspecific lipid transfer protein extracted from maize seeds

Source

Protein science : a publication of the Protein Society, 1996, vol. 5, pp. 565-577

Authors (8)

Gomar-J	Petit-M-C
Sodano-P	Sy-D
Marion-D	Kader-J-C
Vovelle-F	Ptak-M

Abstract

The three-dimensional solution structure of a nonspecific lipid transfer protein
extracted from maize seeds determined by 1H NMR spectroscopy is described. This
cationic protein consists of 93 amino acid residues. Its structure was
determined from 1,091 NOE-derived distance restraints, including 929
interresidue connectivities and 197 dihedral restraints (phi, psi, chi 1)
derived from NOEs and 3J coupling constants. The global fold involving four
helical fragments connected by three loops and a C-terminal tail without regular
secondary structures is stabilized by four disulfide bridges. The most striking
feature of this structure is the existence of an internal hydrophobic cavity
running through the whole molecule. The global fold of this protein, very
similar to that of a previously described lipid transfer protein extracted from
wheat seeds (Gincel E et al., 1994, Eur J Biochem 226:413-422) constitutes a new
architecture for alpha-class proteins. 1H NMR and fluorescence studies show that
this protein forms well-defined complexes in aqueous solution with
lysophosphatidylcholine. Dissociation constants, Kd, of 1.9 +/- 0.6 x 10(-6) M
and > 10(-3) M were obtained with lyso-C16 and -C12, respectively. A structure
model for a lipid-protein complex is proposed in which the aliphatic chain of
the phospholipid is inserted in the internal cavity and the polar head interacts
with the charged side chains located at one end of this cavity. Our model for
the lipid-protein complex is qualitatively very similar to the recently
published crystal structure (Shin DH et al., 1995, Structure 3:189-199).