Abstract
Recent advancements in cryo-electron microscopy (cryo-EM) have greatly facilitated the high-resolution structural determination of macromolecular complexes in their native states. The resultant deeper understanding of the structural mechanisms of protein complexes has improved our accessibility, not only to the field of structural biology but also to various biological phenomena. The structural analysis of proteins using cryo-EM, particularly single-particle analysis (SPA), entails the reconstruction of protein maps, which relies on the symmetry parameters of these proteins to obtain a more accurate map with the aid of image processing. In this paper, we present in the case of strong icosahedral symmetric complex, dihydrolipoyl acetyltransferase (E2) inner core complex of the pyruvate dehydrogenase complex (PDC) and obtain the reconstruction of identical 3D maps using five different symmetry parameters, including C1 without symmetric restraints to examine the impact of symmetry parameters for detailed structural analysis with a higher resolution. The results shows that the reconstructions using inappropriate symmetric parameters produce structurally identical 3D models even at the near-atomic level. Our findings convey a crucial message that should not be disregarded by researchers delving into SPA using relatively user-friendly and convenient image processing software for improved 3D model.