4UHP

Crystal structure of the pyocin AP41 DNase-Immunity complex

Summary for 4UHP

• Entry DOI: 10.2210/pdb4uhp/pdb
• Related: 4UHQ
• Descriptor: LARGE COMPONENT OF PYOCIN AP41, BACTERIOCIN IMMUNITY PROTEIN (3 entities in total)
• Functional Keywords: hydrolase, bacteriocin, dnase, pyocin, dnase-im
• Biological source: PSEUDOMONAS AERUGINOSA PAO1; More
• Total number of polymer chains: 8
• Total formula weight: 106087.61

Authors

Joshi, A.,Chen, S.,Wojdyla, J.A.,Kaminska, R.,Kleanthous, C. (deposition date: 2015-03-25, release date: 2015-08-05, Last modification date: 2024-01-10)

Primary citation

Joshi, A.,Grinter, R.,Josts, I.,Chen, S.,Wojdyla, J.A.,Lowe, E.D.,Kaminska, R.,Sharp, C.,Mccaughey, L.,Roszak, A.W.,Cogdell, R.J.,Byron, O.,Walker, D.,Kleanthous, C.
Structures of the Ultra-High Affinity Protein-Protein Complexes of Pyocins S2 and Ap41 and Their Cognate Immunity Proteins from Pseudomonas Aeruginosa
J.Mol.Biol., 427:2852-, 2015

PubMed Abstract: How ultra-high-affinity protein-protein interactions retain high specificity is still poorly understood. The interaction between colicin DNase domains and their inhibitory immunity (Im) proteins is an ultra-high-affinity interaction that is essential for the neutralisation of endogenous DNase catalytic activity and for protection against exogenous DNase bacteriocins. The colicin DNase-Im interaction is a model system for the study of high-affinity protein-protein interactions. However, despite the fact that closely related colicin-like bacteriocins are widely produced by Gram-negative bacteria, this interaction has only been studied using colicins from Escherichia coli. In this work, we present the first crystal structures of two pyocin DNase-Im complexes from Pseudomonas aeruginosa, pyocin S2 DNase-ImS2 and pyocin AP41 DNase-ImAP41. These structures represent divergent DNase-Im subfamilies and are important in extending our understanding of protein-protein interactions for this important class of high-affinity protein complex. A key finding of this work is that mutations within the immunity protein binding energy hotspot, helix III, are tolerated by complementary substitutions at the DNase-Immunity protein binding interface. Im helix III is strictly conserved in colicins where an Asp forms polar interactions with the DNase backbone. ImAP41 contains an Asp-to-Gly substitution in helix III and our structures show the role of a co-evolved substitution where Pro in DNase loop 4 occupies the volume vacated and removes the unfulfilled hydrogen bond. We observe the co-evolved mutations in other DNase-Immunity pairs that appear to underpin the split of this family into two distinct groups.

PubMed: 26215615
DOI: 10.1016/J.JMB.2015.07.014

Experimental method

X-RAY DIFFRACTION (2 Å)