The First Residue of the PWWP Motif Modulates HATH Domain Binding, Stability, and Protein鈥揚rotein Interaction

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• 作者：Yi-Lin Hung ; Hsia-Ju Lee ; Ingjye Jiang ; Shang-Chi Lin ; Wei-Cheng Lo ; Yi-Jan Lin ; Shih-Che Sue
• 刊名：Biochemistry
• 出版年：2015
• 出版时间：July 7, 2015
• 年：2015
• 卷：54
• 期：26
• 页码：4063-4074
• 全文大小：743K
• ISSN：1520-4995

文摘

Hepatoma-derived growth factor (hHDGF) and HDGF-related proteins (HRPs) contain conserved N-terminal HATH domains with a characteristic structural motif, namely the PWWP motif. The HATH domain has attracted attention because of its ability to bind with heparin/heparan sulfate, DNA, and methylated histone peptide. Depending on the sequence of the PWWP motif, HRP HATHs are classified into P-type (Pro-His-Trp-Pro) and A-type (Ala-His-Trp-Pro) forms. A-type HATH is highly unstable and tends to precipitate in solution. We replaced the Pro residue in P-type HATH_HDGF with Ala and evaluated the influence on structure, dynamics, and ligand binding. Nuclear magnetic resonance (NMR) hydrogen/deuterium exchange and circular dichroism (CD) measurements revealed reduced stability. Analysis of NMR backbone ¹⁵N relaxations (R₁, R₂, and nuclear Overhauser effect) revealed additional backbone dynamics in the interface between the 尾-barrel and the C-terminal helix bundle. The 尾1鈭捨? loop, where the AHWP sequence is located, has great structural flexibility, which aids HATH鈥揌ATH interaction through the loop. A-type HATH, therefore, shows a stronger tendency to aggregate when binding with heparin and DNA oligomers. This study defines the role of the first residue of the PWWP motif in modulating HATH domain stability and oligomer formation in binding.