Abstract: In order to reveal the construction features of goat insulin-like growth factor-binding proteins 1 (GFBP-1) IGFBP-1 in the molecular level and provide a theoretical basis for further study on its protein expression and physical function in goat. Sequence of IGFBP-1 CDS from liver of newborn Nanjiang Mongolian Grazelle, and of other 19 species from NCBI, were analyzed using biology softwares, including ExPasy, NetPhos, NetOGlyc and SignalP. The complete coding region of goat IGFBP-1 encoded 263 amino acid residues. The theory value of IGFBP-1 pI and Mw was 6.33 and 28.5758 ku, respectively. IGFBP-1 was not a globular protein and the instability index (II) amounted to 53.15, and localized extracellularly. The first 25 amino acid residues formed signal peptide, and there were two hydrophilic regions and four hydrophobic regions in primary sequence of goat IGFBP-1, but no transmembrane helices existed in mature protein. Followed by alpha helix and extended strand, random coil was most popular in the secondary structure. 17 phosphorylation sites (11 Ser sites) and eight o-glycosylation sites (7 Thr sites) were predicted, however, the latter had low confident score. The nucleotide and amino acid sequences of IGFBP-1 gene in different species were highly conservative, there were 99% and 98% homology with sheep and bovine at both levels. Further studies showed that the N-terminal domain(26-110) or the C-terminal domain(204-263) of IGFBP-1 shared similarity more than 50% among species, however, the signal peptide(1-25) and midregion(111-203) varied dramatically, for example, goat had the same linked region with sheep, while shared 9% similarity with human. Several motifs including a new segment (FYLPNC) were consistency among 20 species too, while RGD and YF had variants in zebrafish and chicken. The results indicated that IGFBP-1 of goat was an unstable, weakly hydrophilic secretory protein with signal peptide, whose conservation was high among species and not glycosylation but phosphorylation was the main factor to regulate its function.

Key words: goat; IGFBP-1 gene; bioinformatics analysis