英國《BMC生物技術》雜誌刊登一項報告說，美國研究人員發明了用玉米製造出可用於人類的膠原蛋白，其優點是安全、成本低。
據介紹，膠原蛋白是人和許多動物體內都含有的一種蛋白質，用途包括手術後敷在傷口上止血、美容上用於修復皮膚凹痕以及用於製作口服保健品等。現在人們常從動物組織中提取膠原蛋白，但使用動物膠原蛋白的問題是，它們給人體造成感染的風險較大，成本也較高。
相比之下來源於植物的膠原蛋白感染風險較小，但需要解決的一個問題是，源於植物的蛋白質需要經過名為羥基化的過程，才能成為可在人體中正常發揮功能的膠原蛋白。美國艾奧瓦州立大學等機構的研究人員報告說，他們通過向玉米中加入一個基因解決了這個問題，這樣的轉基因玉米可以直接用來製造能用於人類的膠原蛋白。
研究人員說，玉米易於種植、儲存和加工處理，用玉米製造膠原蛋白，與從動物組織中提取膠原蛋白相比成本更低，因此本次成果為生產膠原蛋白提供了一個較好的替代來源。（生物谷Bioon.com）
生物谷推薦原文出處：
BMC Biotechnology doi:10.1186/1472-6750-11-69
Hydroxylation of recombinant human collagen type I alpha 1 in transgenic maize co-expressed with a recombinant human prolyl 4-hydroxylase
Xing Xu , Qinglei Gan , Richard C Clough , Kamesh M Pappu , John A Howard , Julio A Baez and Kan WangBackground
Collagens require the hydroxylation of proline (Pro) residues in their triple-helical domain repeating sequence Xaa-Pro-Gly to function properly as a main structural component of the extracellular matrix in animals at physiologically relevant conditions. The regioselective proline hydroxylation is catalyzed by a specific prolyl 4-hydroxylase (P4H) as a posttranslational processing step.
Results
A recombinant human collagen type I alpha-1 (rCIalpha1) with high percentage of hydroxylated prolines (Hyp) was produced in transgenic maize seeds when co-expressed with both the alpha- and beta- subunits of a recombinant human P4H (rP4H). Germ-specific expression of rCIalpha1 using maize globulin-1 gene promoter resulted in an average yield of 12 mg/kg seed for the full-length rCIalpha1 in seeds without co-expression of rP4H and 4 mg/kg seed for the rCIalpha1 (rCIalpha1-OH) in seeds with co-expression of rP4H. High-resolution mass spectrometry (HRMS) analysis revealed that nearly half of the collagenous repeating triplets in rCIalpha1 isolated from rP4H co-expressing maize line had the Pro residues changed to Hyp residues. The HRMS analysis determined the Hyp content of maize-derived rCIalpha1-OH as 18.11%, which is comparable to the Hyp level of yeast-derived rCIalpha1-OH (17.47%) and the native human CIa1 (14.59%), respectively. The increased Hyp percentage was correlated with a markedly enhanced thermal stability of maize-derived rCIalpha1-OH when compared to the non-hydroxylated rCIalpha1.
Conclusions
This work shows that maize has potential to produce adequately modified exogenous proteins with mammalian-like post-translational modifications that may be require for their use as pharmaceutical and industrial products.