Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands.
Biochemistry. 2021 Apr 20;60(15):1178-1190. doi: 10.1021/acs.biochem.0c00974. Epub 2021 Mar 22.
Phospholipase A/acyltransferase 3 (PLAAT3) and PLAAT4 are enzymes involved in the synthesis of bioactive lipids. Despite sequential and structural similarities, the two enzymes differ in activity and specificity. The relation between the activity and dynamics of the N-terminal domains of PLAAT3 and PLAAT4 was studied. PLAAT3 has a much higher melting temperature and exhibits less nanosecond and millisecond dynamics in the active site, in particular in loop L2(B6), as shown by NMR spectroscopy and molecular dynamics calculations. Swapping the L2(B6) loops between the two PLAAT enzymes results in strongly increased phospholipase activity in PLAAT3 but no reduction in PLAAT4 activity, indicating that this loop contributes to the low activity of PLAAT3. The results show that, despite structural similarity, protein dynamics differ substantially between the PLAAT variants, which can help to explain the activity and specificity differences.
磷脂酶 A/酰基转移酶 3（PLAAT3）和 PLAAT4 是参与生物活性脂质合成的酶。尽管具有序列和结构上的相似性，但这两种酶在活性和特异性上存在差异。研究了 PLAAT3 和 PLAAT4 的 N 端结构域的活性和动力学之间的关系。NMR 光谱和分子动力学计算表明，PLAAT3 的熔点高得多，并且在活性部位的纳秒和毫秒动力学方面表现出较少的变化，特别是在环 L2（B6）中。在两种 PLAAT 酶之间交换 L2（B6）环会导致 PLAAT3 的磷脂酶活性大大增加，而 PLAAT4 的活性没有降低，这表明该环有助于 PLAAT3 的低活性。结果表明，尽管结构相似，但 PLAAT 变体之间的蛋白质动力学存在很大差异，这有助于解释活性和特异性差异。
