發展具金屬鍵結能力之短鏈胜肽

Development of Peptides with Metal Binding Ability

莊慧瀅(Hui-Ying Chuang)

指導教授 ： 陳惠亭

高雄醫學大學/藥學院/香粧品學系碩士班/碩士(2012年)

摘要

本研究利用固相胜肽合成法合成目標胜肽序列共十條，並觀察胜肽添加各種二價金屬離子後，所誘導之二級結構變化與其表面型態的差異時發現，在70 % TFE溶液中，當胜肽1c在添加鈣離子或鉛離子（一當量）時，其胜肽構型即可由無序構型轉變成螺旋類似結構；然而銅離子的影響則需在更高比例量才存在，顯然其構型受鈣、鉛離子影響最劇。另一胜肽2c即可自發性地產生典型螺旋構型，在添加入不同金屬離子後，其二級結構變化較少。由此可證明兩胜肽對金屬螯合之選擇性不同。藉由改變序列組成或順序(peptide3-6)可提升胜肽與鈣離子結合之能力。從穿透式電子顯微鏡觀察，發現目標胜肽添加鈣離子後出現短棒狀聚集，添加銅離子後則出現細長棒狀或片狀聚集，而添加鉛離子後，則形成瓣狀或點狀聚集，可見不同金屬誘導後對其聚集型態之影響不同。以上成果可以作為開發金屬鍵結胜肽在皮膚治療，化粧品應用與減少重金屬污染等應用領域之發展基礎。

關鍵字

固相胜肽合成法 ； 金屬誘導構型變化 ； 金屬誘導聚集

並列摘要

In this study, 10 peptides were synthesized through solid phase peptide synthesis (SPPS) approach. The induced alterations of secondary structures and the differences of morphology were observed by adding divalent metal ions. Upon the addition of Ca2+ or Pb2+ (1 eq) , the conformation of peptide-1c was changed from random coil to alpha-helix like structures, however, similar behavior was observed by addition of Cu2+ in higher proportion. Remarkably the conformation was affected most by Ca2+ and Pb2+. Another peptide, peptide-2c formed the typical alpha-helix structure by itself. It showed less affect by Ca2+ as much as Cu2+, and Pb2+. These observations indicated that the metal selectivity of two target peptides were different. Moreover, the peptides with alternated residues or sequences (peptide 3-6) increased the interaction with calcium ions. From the TEM images, the target peptides formed short rod aggregation after adding Ca2+, slender rod or sheet aggregation upon addition of Cu2+, and petal-like or punctate aggregation after adding Pb2+. The results showed different aggregations were induced by different metal ions. These discoveries can serve as fundamentals for the development of metal binding peptides for skin treatment, cosmetic applications and removing heavy metal pollution.

並列關鍵字

Solid phase peptide synthesis ； metal-induced conformational change ； metal-induced assembly

參考文獻

Dudev, T.; Lim, C. Metal binding affinity and selectivity in metalloproteins. Annual Review of Biophysics, 2008, 37, 97-116.

Thompson, L. C.; Goswami, S.; Peterson, C.B. Metals affect the structure and activity of human plasminogen activator inhibitor-1. II. Binding affinity and conformational changes. Protein Science, 2011, 20, 366-378.

Lovell, T.; Himo, F.; Han, WG.; Noodleman, L. Density functional methods applied to metalloenzymes. Coordination Chemistry Reviews, 2003, 238, 211-232.

Dudev, T.; Lim, C. Principles governing Mg, Ca, and Zn binding and selectivity in proteins. Chemical Reviews, 2003, 103, 773-787.

Dudev, T.; Lim, C. Metal-binding affinity and selectivity of nonstandard natural amino acid residues from DFT/CDM calculations. The Journal of Physical Chemistry B, 2009, 113, 11754-11764.