Allosteric regulation in a family of enterobacterial aspartate transcarbamylases: intramolecular transmission of regulatory signals in chimeric enzymes.
Allosteric regulation in a family of enterobacterial aspartate transcarbamylases: intramolecular transmission of regulatory signals in chimeric enzymes.
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肠细菌天冬氨酸转氨甲酰酶家族的变构调节：嵌合酶中调节信号的分子内传递。
DOI：
10.1006/jmbi.1996.0511
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Wild,JR
中科院分区：
文献类型：
--
作者：
Cunin,R;Wales,ME;VanVliet,F;DeStaercke,C;Scapozza,L;Rani,CS;Wild,JR
几种肠杆菌天冬氨酸氨基转移酶(ATCase)具有类似于大肠杆菌的[2(C3)：3(R2)]四级结构。尽管它们保守的四级结构，但这些酶在底物结合的协作性和核苷酸效应器对它们的变构调节方面存在着实质性的差异。不同酶种之间的比较为我们提供了一个机会来扩大我们对ATCase中变构的分子基础的理解。通过交换与四级结构特征有关的亚结构域，如本研究中分析的R1-C4调节-催化亚单位界面，构建了嵌合ATCase，以确定该界面参与变构调节的几个组成部分。研究发现，在粘质沙雷氏菌和普通变形杆菌中，r1-c4界面是识别和传递ATP调节信号的重要元件，就像在你体内一样。结肠酶。此外，调节链C-末端区域的特定氨基酸组成及其与催化链240S环中氨基酸残基的相互作用(R1-C4相互作用)调节了酶对ATP的反应幅度。调节链的C-末端区域似乎没有直接参与CTP对三种天然ATCase的调节。即使当CTP充当激活剂时，就像在Thep中一样。粗俗和粗俗。MarcescensATCase，它的信号遵循与一般激活剂ATP不同的路线。CTP和UTP的协同抑制作用涉及到特定的UTP信号的传递。这一信号在不同的ATCase中表现不同，涉及调控链的C-末端区域。科兰德·S。MarcescensATCase，但不在Thep.庸俗的ATCase
Several enterobacterial aspartate transcarbamylases (ATCases) exhibit a [2(c3):3(r2)] quaternary structure analogous to that of theEscherichia colienzyme. Despite their conserved quaternary structures, these enzymes present substantial differences in the co-operativity of substrate binding and in their allosteric regulation by nucleotide effectors. A comparison between different enzymatic species provides an opportunity to expand our understanding of the molecular basis of allostery in ATCase. Chimeric ATCases were constructed by exchanging subdomain regions involved in quaternary structural features, such as the r1-c4 regulatory-catalytic subunit interface analyzed in this study, in order to define the involvement of this interface in the several components of allosteric regulation. The r1-c4 interface was found to constitute an essential element for the recognition and the transmission of the ATP regulatory signal in theSerratia marcescensand theProteus vulgarisATCases, as it does in theE. coliATCase. Besides, the specific amino acid composition of the C-terminal region of the regulatory chain and its interactions with the amino acid residues in the 240s loop of the catalytic chain (r1-c4 interactions) were found to modulate the amplitude of the enzyme's response to ATP. The C-terminal region of the regulatory chain did not appear to participate directly in the regulation of the three native ATCases by CTP. Even when CTP acts as an activator, as in theP. vulgarisandS. marcescensATCases, its signal follows a route distinct from that of the general activator ATP. Synergistic inhibition by CTP and UTP was found to involve the transmission of a specific UTP signal. This signal appeared different in the various ATCases, involving the C-terminal region of the regulatory chain in theE. coliandS. marcescensATCases but not in theP. vulgarisATCase.