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Figure 6
Hydrogen-bond contacts between the signal peptide and SpsB. A stereo figure showing an inhibitory signal peptide (yellow) bound to SpsB. The peptide makes main-chain parallel β-­sheet hydrogen-bond interactions (dashes) with strands that line the peptide-binding cleft, but makes no contact with SpsB before residue P5 or after residue P3′. The side chain of Ser36 is directed at the plane of the P1 scissile bond, with its Oγ atom 2.9 Å from the carbonyl C atom. The rigid P1′ proline pyrrolidine ring Cα atom prevents the P1 carbonyl C atom from moving closer to Ser36. Water is shown as a red sphere.

IUCrJ
Volume 3| Part 1| January 2016| Pages 10-19
ISSN: 2052-2525
doi:10.1107/S2052252515019971