English  |  正體中文  |  简体中文  |  Items with full text/Total items : 28611/40649
Visitors : 617948      Online Users : 83
RC Version 4.0 © Powered By DSPACE, MIT. Enhanced by NTU Library IR team.
Scope Adv. Search

Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/43382

Title: An additional H-bond in the a1b2 interface as the structure basis for the low oxygen affinity and high cooperativity of a novel recombinant hemoglobin (bL105W)
Authors: Tsuei-Yun Fang;Virgil Simplaceanu;Ching-Hsuan Tsai;Nancy T. Ho;Chien Ho
Contributors: 國立臺灣海洋大學:食品科學系
Date: 2000-10
Issue Date: 2017-07-24T02:13:40Z
Publisher: Biochemistry
Abstract: Abstract:Site-directed mutagenesis has been used to construct three recombinant mutant hemoglobins (rHbs), rHb(βL105W), rHb(αD94A/βL105W), and rHb(αD94A). rHb(βL105W) is designed to form a new hydrogen bond from β105Trp to α94Asp in the α1β2 subunit interface to lower the oxygen binding affinity by stabilizing the deoxy quaternary structure. We have found that rHb(βL105W) does indeed possess a very low oxygen affinity and maintains normal cooperativity (P50 = 28.2 mmHg, nmax = 2.6 in 0.1 M sodium phosphate at pH 7.4) compared to those of Hb A (P50 = 9.9 mmHg, nmax = 3.2 at pH 7.4). rHb(αD94A/βL105W) and rHb(αD94A) are expressed to provide evidence that rHb(βL105W) does form a new H-bond from β105Trp to α94Asp in the α1β2 subunit interface of the deoxy quaternary structure. Our multinuclear, multidimensional nuclear magnetic resonance (NMR) studies on 15N-labeled rHb(βL105W) have identified the indole nitrogen-attached 1H resonance of β105Trp for rHb(βL105W). 1H NMR studies on Hb A and mutant rHbs have been used to investigate the structural basis for the low O2 affinity of rHb(βL105W). Our NMR results provide evidence that rHb(βL105W) forms a new H-bond from β105Trp to α94Asp in the α1β2 subunit interface of the deoxy quaternary structure. The NMR results also show that these three rHbs can switch from the R quaternary structure to the T quaternary structure in their ligated state upon addition of an allosteric effector, inositol hexaphosphate. We propose that the low O2 affinity of rHb(βL105W) is due to the formation of a new H-bond between α105Trp and α94Asp in the deoxy quaternary structure.
Relation: 39(45), pp.13708-13718
URI: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/43382
Appears in Collections:[食品科學系] 期刊論文

Files in This Item:

File Description SizeFormat

All items in NTOUR are protected by copyright, with all rights reserved.


著作權政策宣告: 本網站之內容為國立臺灣海洋大學所收錄之機構典藏,無償提供學術研究與公眾教育等公益性使用,請合理使用本網站之內容,以尊重著作權人之權益。
網站維護: 海大圖資處 圖書系統組
DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU Library IR team Copyright ©   - Feedback