Variable-resolution maps (VRMs) in CCTBX and Phenix: accounting for local resolution in cryoEM

Afonine, P.V.; Adams, P.D.; Urzhumtsev, A.G.

doi:10.1107/S2052252526008201

Figure 5
Difference, in e Å⁻³, as a function of the distance r to the atomic center, between the atomic image (8–9) for atoms of C, Fe and Au, and several approximations (1)

to it, varying the number of terms K. A green bar at the axis shows the value $[\rho \left(0 \right)]$ of the respective atomic image at its center divided by 100. $[\Delta\rho_{\max}]$ is computed for images of resolution $[{d_{\rm min}}]$ of 2 Å and 5 Å up to the distance limit $[5{d_{\rm min}}]$ . Colored arrows matching the curves' colors indicate the value of the largest $[{R^{\left(k \right)}}]$ for the given approximation. Terms with $[{R^{\left(k \right)}} \le {r_{\rm max}}]$ (considered here as $[2.5{d_{\rm min}}]$ , $[3.0{d_{\rm min}}]$ , $[3.5{d_{\rm min}}]$ and $[\,4.0{d_{\rm min}}]$ ) may be insufficient to produce an accurate approximation for the points close to $[{r_{\rm max}}]$ and one or two next terms beyond $[{R^{\left(k \right)}}]$ may notably reduce the error.

IUCrJ

Volume 13| Part 6| November 2026|

ISSN: 2052-2525

https://doi.org/10.1107/S2052252526008201

CRYO | EM

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