Note to the Paper by Guasch et al. (2002) Detailed Architecture of a DNA Translocating Machine: The High-resolution Structure of the Bacteriophage φ29 Connector Particle

Abstract

The recent paper by Guasch et al.1 describing the structure of the ϕ29 bacteriophage head–tail connector at 2.1 A resolution (PDB code 1h5w), makes reference to the original 3.2 A resolution structure (PDB code 1fou) published by Simpson et al.2 and used by Guasch et al. to solve the 1h5w structure by molecular replacement. The Guasch paper states that there are marked differences between the 1h5w and 1fou structures in the chain tracing and the side-chain positioning in the wide domain. As these and a number of other statements in the Guasch paper may have led to the impression that these differences are larger than they really are, we give here Tables summarizing the similarities and differences (Tables 1 and ​and22). Table 1 Statistical comparison of the ϕ29 connector wide domains in different structures Table 2 Superposition of the entire monomers in the four reported structures Another paper by Simpson et al.,3 which was accidentally omitted from the text of the Guasch et al. paper, reports two additional structures of the ϕ29 connector: at 3.2 A resolution and at 2.9 A resolution (PDB codes 1jnb and 1ijg, respectively). The 2.9 A resolution structure shows no significant differences from the structure subsequently reported by Guasch et al. (Figure 1; Tables 1 and ​and22). Figure 1 Stereo diagram showing the superposition of the Cα back-bone of monomer A in the 2.1 A resolution structure 1h5w (green) and the 2.9 A resolution 1ijg structure (red).