Title : Glycosylation analysis and
protein structure determination of murine fetal antigen 1 (
mFA1 )--the circulating gene product of the
delta-like protein (
dlk ),
preadipocyte factor 1 (
Pref-1 ) and
stromal-cell-derived protein 1 (
SCP-1 ) cDNAs
Abstract :
- By means of sequence analysis, murine fetal antigen 1 ( mFA1 ) isolated from Mus musculus amniotic fluid was shown to be the circulating protein of the delta-like protein , stromal-cell-derived protein 1 ( SCP-1 ) and preadipocyte factor 1 ( Pref-1 ) gene products
- The protein contains 36 cysteine residues arranged in six epidermal-growth-factor-like domains
- The purification of several C-terminal peptides of varying lengths showed mFA1 to be C-terminal heterogeneous
- O-linked glycosylations of the NeuNAc alpha2-3Gal beta1-3(NeuNAc alpha2-6)GalNAc type were present on all C-terminal peptides at residues Thr235, Thr244 and Thr248 , although glycosylation on Thr244 was only partial
- Three N-linked glycosylations were localized in mFA1 ( Asn77, Asn142 and Asn151 ), two of which ( Asn142 and Asn151 ) were in the unusual Asn-Xaa- Cys motif
- Fucosylated biantennary complex-type and small amounts (less than 5%) of triantennary complex-type structures were identified on the glycosylated asparagine residues using sequential exoglycosidase and endoglycosidase digestions combined with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS)
- The presence of O-linked monosaccharides (glucose attached to Ser71, Ser193 and fucose at Thr201 ) was tentatively ascertained by combining Edman degradation and MALDI-MS
- The results presented shows mFA1 to be the circulating heterogeneous cleavage products of the membrane-bound protein encoded by the murine cDNAs dlk , pref-1 and SCP-1