Bartos, L.; Pajtinka, P.; Vacha, R.

Lipid order parameters are an important metric for quantifying the molecular structure of biological membranes. They can be derived from both molecular simulations and experimental measurements, enabling robust comparisons between the two. Although methods for calculating lipid order parameters from molecular dynamics simulations of membrane systems at various resolutions are well established, a comprehensive and user-friendly package for these calculations is lacking, which has even led some researchers to use tools that are known to perform the calculations incorrectly. To address this, we have developed gorder, an analysis tool capable of calculating lipid order parameters in atomistic, united-atom, and coarse-grained systems, compatible with any force field, and applicable to both planar and curved membrane geometries. gorder is designed to be fast and versatile, providing a unified solution for lipid order calculations. The tool is freely available from crates.io/crates/gorder and github.com/Ladme/gorder under the MIT License.