Reference "Phospholipid transfer protein: full-length cDNA and amino acid sequence in maize. Amino acid sequence homologies between plant phospholipid transfer proteins"

Reference ID

7273

Title

Phospholipid transfer protein: full-length cDNA and amino acid sequence in maize. Amino acid sequence homologies between plant phospholipid transfer proteins

Source

The Journal of biological chemistry, 1988, vol. 263, pp. 16849-16855

Authors (10)

Tchang-F	This-P
Stiefel-V	Arondel-V
Morch-M-D	Pages-M
Puigdomenech-P	Grellet-F
Delseny-M	Bouillon-P

Abstract

We have determined the primary structure of a phospholipid transfer protein
(PLTP) isolated from maize seeds. This protein consists of 93 amino acids and
shows internal homology originating in the repetition of (do)decapeptides. By
using antibodies against maize PLTP, we have isolated from a cDNA library one
positive clone (6B6) which corresponds to the incomplete nucleotide sequence.
Another cDNA clone (9C2) was obtained by screening a size-selected library
with 6B6. Clone 9C2 (822 base pairs) corresponds to the full-length cDNA of
the phospholipid-transfer protein whose mRNA contains 0.8 kilobase. Southern
blot analysis shows that the maize genome may contain several PLTP genes. In
addition, the deduced amino acid sequence of clone 9C2 reveals the presence of
a signal peptide. The significance of this signal peptide (27 amino acids)
might be related to the function of the phospholipid-transfer protein. The
amino acid sequence of maize PLTP was compared to those isolated from spinach
leaves or castor bean seeds which exhibit physicochemical properties close to
those of the maize protein. A high homology was observed between the three
sequences. Three domains can be distinguished: a highly charged central core
(around 40-60), a very hydrophobic N-terminal sequence characteristic of polypeptide-
membrane interaction, and a hydrophilic C terminus. A model for plant phospholipid-
transfer proteins is proposed in which the phospholipid molecule is embedded
within the protein with its polar moiety interacting with the central
hydrophilic core of the protein, whereas the N-terminal region plunges within
the membrane in the transfer process.