Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/22764
Title: Structural Determinants in the folding of epidermal growth factor (EGF)-Like domains
Authors: NG AH SOCK ANGIE
Keywords: protein folding code, structural determinants, epidermal growth factor-like domains
Issue Date: 11-Jan-2011
Citation: NG AH SOCK ANGIE (2011-01-11). Structural Determinants in the folding of epidermal growth factor (EGF)-Like domains. ScholarBank@NUS Repository.
Abstract: The epidermal growth factor (EGF)-like domain is an evolutionarily conserved modular protein subunit. Despite hypervariability of amino acid sequences in their inter-cysteine region, they preferentially fold into a three-looped conformation with a disulfide pairing of C₁-C₃, C₂-C₄, C₅-C₆. To elucidate the structural determinants that dictates the canonical EGF-like domain fold, we had chosen the fourth and fifth EGF-like domain of thrombomodulin (TM) as models. While the fourth EGF-like domain folds into the canonical conformation, the fifth EGF-like domain does not and possesses an alternate disulfide pairing of C₁-C₂, C₃-C₄, C₅-C₆. We examined the folding tendencies of two synthetic peptides corresponding to truncated versions of TM EGF-like domain four and five under air oxidation and redox folding conditions. By identifying the structural isoforms obtained in the folding reaction using regiospecifically-synthesized conformers as controls, we determined that the last segment of both domains (encompassing C₅ and C₆) do not influence the tendencies to fold into their respective native conformations. When folded under denaturing conditions, the folding tendency of the fourth EGF-like domain changes to that of the C₁-C₂, C₃-C₄ conformer. Conversely, the addition of denaturant did not affect the folding tendency of the fifth EGF-like domain. This suggests that side chain interactions are crucial for achieving the canonical EGF-like domain fold but not for the non-canonical fold. Folding under high salt content did not disrupt the folding tendencies of both domains and result in slight increase of the C₁-C₃, C₂-C₄ conformer in both cases. This suggests that hydrophobic interaction, but not electrostatic interaction, is the key in the achieving the canonical fold of EGF-like domains.
URI: http://scholarbank.nus.edu.sg/handle/10635/22764
Appears in Collections:Master's Theses (Open)

Show full item record
Files in This Item:
File Description SizeFormatAccess SettingsVersion 
Structural Determinants in the Folding of EGF-like Domains - Ng Ah Sock Angie (A0019259Y).pdf8.39 MBAdobe PDF

OPEN

NoneView/Download

Page view(s)

239
checked on Dec 16, 2018

Download(s)

112
checked on Dec 16, 2018

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.