Elucidating the Interaction between Pyridoxine 5'-Phosphate Oxidase and Dopa Decarboxylase: Activation of B6-Dependent Enzyme.
Elucidating the Interaction between Pyridoxine 5'-Phosphate Oxidase and Dopa Decarboxylase: Activation of B6-Dependent Enzyme.
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DOI：
10.3390/ijms24010642
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发表时间：
2022-12-30
影响因子：
5.6
通讯作者：
Safo MK
中科院分区：
文献类型：
--
作者：
Al Mughram MH;Ghatge MS;Kellogg GE;Safo MK
5'-磷酸吡哆醛 (PLP) 是维生素 B6 的活性形式，是参与许多细胞过程的多种 B6 依赖性（PLP 依赖性）酶的辅助因子。其中一种 B6 酶是多巴脱羧酶 (DDC)，它是关键神经递质（例如多巴胺和血清素）生物合成所必需的。 PLP依赖性酶被生物合成为apo-B6酶，然后通过PLP的醛和蛋白质的活性位点赖氨酸之间形成席夫碱而转化为具有催化活性的holo-B6酶。在真核生物中，PLP 通过 B6 补救酶、吡哆醇 5'-磷酸氧化酶 (PNPO) 和吡哆醛激酶 (PLK) 的活性而可供 B6 酶使用。为了最大限度地减少毒性，细胞通过 PNPO 和 PLK 的去磷酸化和 PLP 反馈抑制，将游离 PLP（未结合）的含量保持在非常低的水平。这导致提出了在 PLP 转移之前 B6 挽救酶和 apo-B6 酶之间形成复合物的机制，尽管此类复合物尚未在原子水平上进行表征，大概是由于其瞬态性质。首次使用计算研究来预测可能的 PNPO 和 DDC 复合物，这表明 PNPO 上的变构 PLP 紧密结合位点与 DDC 的活性位点之间存在接触。使用等温量热法和/或表面等离子共振，我们还表明 PNPO 结合 apoDDC 和 holoDDC，解离常数分别为 0.93 ± 0.07 μM 和 2.59 ± 0.11 μM。最后，在apoDDC存在的情况下，PNPO上紧密结合的PLP被转移到apoDDC上，从而形成约35%的holoDDC。
Pyridoxal 5′-phosphate (PLP), the active form of vitamin B6, serves as a cofactor for scores of B6-dependent (PLP-dependent) enzymes involved in many cellular processes. One such B6 enzyme is dopa decarboxylase (DDC), which is required for the biosynthesis of key neurotransmitters, e.g., dopamine and serotonin. PLP-dependent enzymes are biosynthesized as apo-B6 enzymes and then converted to the catalytically active holo-B6 enzymes by Schiff base formation between the aldehyde of PLP and an active site lysine of the protein. In eukaryotes, PLP is made available to the B6 enzymes through the activity of the B6-salvage enzymes, pyridoxine 5′-phosphate oxidase (PNPO) and pyridoxal kinase (PLK). To minimize toxicity, the cell keeps the content of free PLP (unbound) very low through dephosphorylation and PLP feedback inhibition of PNPO and PLK. This has led to a proposed mechanism of complex formation between the B6-salvage enzymes and apo-B6 enzymes prior to the transfer of PLP, although such complexes are yet to be characterized at the atomic level, presumably due to their transient nature. A computational study, for the first time, was used to predict a likely PNPO and DDC complex, which suggested contact between the allosteric PLP tight-binding site on PNPO and the active site of DDC. Using isothermal calorimetry and/or surface plasmon resonance, we also show that PNPO binds both apoDDC and holoDDC with dissociation constants of 0.93 ± 0.07 μM and 2.59 ± 0.11 μM, respectively. Finally, in the presence of apoDDC, the tightly bound PLP on PNPO is transferred to apoDDC, resulting in the formation of about 35% holoDDC.
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影响因子：
14.8
作者：
Kozakov D;Hall DR;Xia B;Porter KA;Padhorny D;Yueh C;Beglov D;Vajda S
通讯作者：
Vajda S
DOI：
10.1038/nsb1101-963
发表时间：
2001-11-01
期刊：
NATURE STRUCTURAL BIOLOGY
影响因子：
--
作者：
Burkhard, P;Dominici, P;Malashkevich, VN
通讯作者：
Malashkevich, VN
影响因子：
3.9
作者：
Bertoldi, Mariarita
通讯作者：
Bertoldi, Mariarita
影响因子：
2.9
作者：
CHARTERIS, A;JOHN, R
通讯作者：
JOHN, R
影响因子：
5.4
作者：
Durrant JD;McCammon JA
通讯作者：
McCammon JA