Fraunhofer Institute for Microstructure of Materials and Systems (IMWS), Halle (Saale), Germany.
Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
FASEB J. 2019 Apr;33(4):5468-5481. doi: 10.1096/fj.201801860RR. Epub 2019 Jan 24.
Lysyl oxidases (LOXs) play a central role in extracellular matrix remodeling during development and tumor growth and fibrosis through cross-linking of collagens and elastin. We have limited knowledge of the structure and substrate specificity of these secreted enzymes. LOXs share a conserved C-terminal catalytic domain but differ in their N-terminal region, which is composed of 4 repeats of scavenger receptor cysteine-rich (SRCR) domains in LOX-like (LOXL) 2. We investigated by X-ray scattering and electron microscopy the low-resolution structure of the full-length enzyme and the structure of a shorter form lacking the catalytic domain. Our data demonstrate that LOXL2 has a rod-like structure with a stalk composed of the SRCR domains and the catalytic domain at its tip. We detected direct interaction between LOXL2 and tropoelastin (TE) and also LOXL2-mediated deamination of TE. Using proteomics, we identified several allysines together with cross-linked TE peptides. The elastin-like material generated was resistant to trypsin proteolysis and displayed mechanical properties similar to mature elastin. Finally, we detected the codistribution of LOXL2 and elastin in the vascular wall. Altogether, these data suggest that LOXL2 could participate in elastogenesis in vivo and could be used as a means of cross-linking TE in vitro for biomimetic and cell-compatible tissue engineering purposes.-Schmelzer, C. E. H., Heinz, A., Troilo, H., Lockhart-Cairns, M.-P., Jowitt, T. A., Marchand, M. F., Bidault, L., Bignon, M., Hedtke, T., Barret, A., McConnell, J. C., Sherratt, M. J., Germain, S., Hulmes, D. J. S., Baldock, C., Muller, L. Lysyl oxidase-like 2 (LOXL2)-mediated cross-linking of tropoelastin.
赖氨酰氧化酶（LOXs）在细胞外基质重塑中发挥核心作用，在发育、肿瘤生长和纤维化过程中通过胶原蛋白和弹性蛋白的交联发挥作用。我们对这些分泌酶的结构和底物特异性知之甚少。LOXs 具有保守的 C 端催化结构域，但在其 N 端区域不同，该区域由 LOXL2 中的 4 个重复的清道夫受体富含半胱氨酸（SRCR）结构域组成。我们通过 X 射线散射和电子显微镜研究了全长酶的低分辨率结构和缺乏催化结构域的较短形式的结构。我们的数据表明，LOXL2 具有棒状结构，由 SRCR 结构域组成的柄和其尖端的催化结构域组成。我们检测到 LOXL2 与原弹性蛋白（TE）之间的直接相互作用，以及 LOXL2 介导的 TE 脱氨作用。使用蛋白质组学，我们鉴定了几个赖氨酰赖氨酸以及交联的 TE 肽。生成的弹性样物质对胰蛋白酶水解具有抗性，并显示出与成熟弹性蛋白相似的机械性能。最后，我们在血管壁中检测到 LOXL2 和弹性蛋白的共分布。总之，这些数据表明 LOXL2 可参与体内的弹性蛋白生成，并可作为体外交联 TE 的手段，用于仿生和细胞相容的组织工程目的。
