Expression, purification and characterization of fourth FAS1 domain of TGF尾Ip-associated corneal dystrophic mutants

详细信息	查看全文 | 推荐本文 |

• 作者：Murugan Elavazhagan^a ; ¹ ; Rajamani Lakshminarayanan^a ; ¹ ; Lei Zhou^a ; ^c ; Lim Wei Ting^a ; Louis Tong^a ; ^b ; ^c ; ^d ; Roger W. Beuerman^a ; ^b ; ^c ; ^d ; Shyam S. Chaurasia^a ; ^{shyamsunderc@yahoo.com} ; Jodhbir S. Mehta^a ; ^b ; ^c ; ^d ; ^{jodmehta@gmail.com}
• 关键词：TGF尾Ip ; Lattice corneal dystrophies ; Granular corneal dystrophies ; Protein aggregation ; Conformational stability ; Fluorescence spectroscopy
• 刊名：Protein Expression and Purification
• 出版年：2012
• 期刊代码：184_10465928
• 类别：bio
• 出版时间：July, 2012
• 卷：84
• 期：1
• 页码：108-115
• 文件大小：773 K

摘要

Corneal dystrophies (CDs) are a group of inherited bilateral disorders affecting the corneal tissue of the eye. Most of these CDs in the stromal layer of the cornea have been associated with mutations found on the TGFBI gene that codes for a 683-amino acid transforming growth factor induced protein (TGF尾Ip). These mutations have been found to induce atypical aggregation and progressive accumulation of protein aggregates in the cornea that leads to loss of corneal transparency and hence blindness. At present, 65 distinct pathogenic mutations have been identified in TGFBI that are associated with different clinical phenotypes. More than 80%of these missense mutations occur in the 4th FAS (fasciclin-like) 1 domain. Current treatment includes surgical intervention, which often involves high recurrence rates. Hence, it is imperative to examine the properties of the TGF尾Ip and the pathogenic mutant proteins to understand the pathology of the disease mechanism and to develop potent therapeutics. Here, we report the recombinant expression, purification, characterization and the effect of four clinically significant pathogenic TGF尾Ip mutants - R555W, H572R, A620D, and H626R on the biophysical properties of the wild type (WT) 4th FAS1 domain of TGF尾Ip. While a higher proportion of the R555W, H572R and H626R mutants of the 4th FAS1 domains remained stable, the A620D mutant largely existed as inclusion bodies in native state and aggregates under physiological conditions. These mutants present a unique platform to examine protein aggregation-prone diseases wherein single amino-acid mutations present distinct pathogenic phenotypes. Though pathogenically and phenotypically diverse, these mutants do not exhibit variations in secondary structure and stability, except for the A620D mutant, when examined by CD and UV spectroscopy.