Figure 4.

Location of Calcium Ions and Disulfides within the BKV Virion

(A) The calcium binding site in the sharpened BKV map with EM density for calcium shown at 6 σ with surrounding residues colored according to the corresponding chain.

(B) Atomic model of the CD loops of chains 2, 3, and 6 and the N terminus of an adjacent chain 2 from BKV with EM density shown at 1.5 σ.

(C) Density from the unsharpened, non-reduced BKV map low-pass filtered to 7 Å (0.5 σ), showing additional density extending from the N terminus of chain 2 and connecting to the CD loop of an adjacent chain 2.

(D) Analogous region to that shown in (C) from the unsharpened reduced BKV map low-pass filtered to 7 Å (0.5 σ).

(E) Density from the unsharpened BKV map low-pass filtered to 7 Å (1 σ), showing additional density extending from the N terminus of chain 4 and connecting to the CD loop of chain 1.

(F) Analogous region to that shown in (E) from the unsharpened reduced BKV map low-pass filtered to 7 Å (1 σ).