Structural characterizations of glycerol kinase: unraveling phosphorylation-induced long-range activation.
Structural characterizations of glycerol kinase: unraveling phosphorylation-induced long-range activation.
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DOI：
10.1021/bi8009407
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发表时间：
2009-01-20
期刊：
影响因子：
2.9
通讯作者：
Deutscher, Josef
中科院分区：
文献类型：
--
作者：
Yeh, Joanne I.;Kettering, Regina;Saxl, Ruth;Bourand, Alexa;Darbon, Emmanuelle;Joly, Nathalie;Briozzo, Pierre;Deutscher, Josef
甘油代谢是糖和脂肪酸分解代谢的中心环节。在大多数细菌中，甘油激酶在调节通道/促进剂非依赖的甘油摄取进入细胞中起着至关重要的作用。在乳酪肠球菌中，这种酶的活性通过位于其激活环中的组氨酸残基(His232)的磷酸化而增强，该组氨酸残基位于其催化裂隙约25？处。我们早些时候报道过，His232的一些突变改变了酶的活性；我们在这里展示了这些突变的GlpK酶的晶体结构。一种酶活性增强的突变酶His232Arg的结构表明，催化裂隙上的残基更优化地排列以结合ATP并介导磷酸化转移。具体地说，与其在WT、His232Ala和His232Glu酶中的位置相比，Arg18在His232Arg中的位置移动了~1ä。Arg18的这种新构象更优化地定位在三磷酸腺苷的假定γ-磷酸位置，靠近甘油底物。除了活性部位的结构变化外，激活环的构象稳定性也降低了，反映在活性降低的突变酶His232Glu中B因子(“热因子”)增加了~35%。将构象变化与突变酶中酶活性的变化相关联，确定了对分子内信号转导具有深远影响的不同的局部区域。通过二聚体界面上的成对相互作用的改变可以将磷酸化状态从激活环传递到催化裂隙，从而定位Arg18以在β，γ桥接位置形成有利的相互作用。这将抵消三磷酸腺苷在磷酸转移到甘油过程中γ-磷酸的氢键的损失，这表明甘油激酶的第二底物，三磷酸腺苷分子的适当排列可能在很大程度上决定了3-甘油-磷酸的产生速度。
Glycerol metabolism provides a central link between sugar and fatty acid catabolism. In most bacteria, glycerol kinase plays a crucial role in regulating channel/facilitator-independent uptake of glycerol into the cell. In the firmicute Enterococcus casseliflavus, this enzyme’s activity is enhanced by phosphorylation of the histidine residue (His232) located in its activation loop, approximately 25 Å away from its catalytic cleft. We reported earlier that some mutations of His232 altered enzyme activities; we present here the crystal structures of these mutant GlpK enzymes. The structure of a mutant enzyme with enhanced enzymatic activity, His232Arg, reveals that residues at the catalytic cleft are more optimally aligned to bind ATP and mediate phosphoryl transfer. Specifically, the position of Arg18 in His232Arg shifts by ~1 Å when compared to its position in WT, His232Ala, and His232Glu enzymes. This new conformation of Arg18 is more optimally positioned at the presumed γ-phosphate location of ATP, close to the glycerol substrate. In addition to structural changes exhibited at the active site, the conformational stability of the activation loop is decreased, as reflected by ~35% increase in B-factors (“thermal factors”) in a mutant enzyme displaying diminished activity, His232Glu. Correlating conformational changes to alteration of enzymatic activities in the mutant enzymes identifies distinct localized regions that can have profound effects on intramolecular signal transduction. Alterations of pairwise interactions across the dimer interface can communicate phosphorylation states over 25 Å from the activation loop to the catalytic cleft, positioning Arg18 to form favourable interactions at the β,γ-bridging position to ATP. This would offset loss of the hydrogen bonds at the γ-phosphate of ATP during phosphoryl transfer to glycerol, suggesting that appropriate alignment of the second substrate of glycerol kinase, the ATP molecule, may largely determine the rate of glycerol-3-phosphate production.
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影响因子：
8
作者：
COLOVOS, C;YEATES, TO
通讯作者：
YEATES, TO
DOI：
10.1107/s0907444901021758
发表时间：
2002-03-01
期刊：
ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY
影响因子：
--
作者：
Berisio, R;Sica, F;Mazzarella, L
通讯作者：
Mazzarella, L
影响因子：
2.9
作者：
Bystrom, CE;Pettigrew, DW;Remington, SJ
通讯作者：
Remington, SJ
DOI：
10.1073/pnas.80.22.6790
发表时间：
1983-01-01
期刊：
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES
影响因子：
--
作者：
DEUTSCHER, J;SAIER, MH
通讯作者：
SAIER, MH
影响因子：
2.9
作者：
Ormö, M;Bystrom, CE;Remington, SJ
通讯作者：
Remington, SJ