8EE1

KS-AT didomain from module 2 of the 6-deoxyerythronolide B synthase in complex with antibody fragment AA5

Summary for 8EE1

• Entry DOI: 10.2210/pdb8ee1/pdb
• Descriptor: 6-deoxyerythronolide B synthase, AA5 antibody heavy chain, AA5 antibody light chain, ... (4 entities in total)
• Functional Keywords: polyketide synthase, biosynthetic protein, transferase-immune system complex, transferase/immune system
• Biological source: Saccharopolyspora erythraea; More
• Total number of polymer chains: 6
• Total formula weight: 298347.92

Authors

Cogan, D.P.,Brodsky, K.L.,Guzman, K.M.,Mathews, I.I.,Khosla, C. (deposition date: 2022-09-06, release date: 2023-05-31, Last modification date: 2024-10-23)

Primary citation

Guzman, K.M.,Cogan, D.P.,Brodsky, K.L.,Soohoo, A.M.,Li, X.,Sevillano, N.,Mathews, I.I.,Nguyen, K.P.,Craik, C.S.,Khosla, C.
Discovery and Characterization of Antibody Probes of Module 2 of the 6-Deoxyerythronolide B Synthase.
Biochemistry, 62:1589-1593, 2023

PubMed Abstract: Fragment antigen-binding domains of antibodies (Fs) are powerful probes of structure-function relationships of assembly line polyketide synthases (PKSs). We report the discovery and characterization of Fs interrogating the structure and function of the ketosynthase-acyltransferase (KS-AT) core of Module 2 of the 6-deoxyerythronolide B synthase (DEBS). Two Fs (AC2 and BB1) were identified to potently inhibit the catalytic activity of Module 2. Both AC2 and BB1 were found to modulate ACP-mediated reactions catalyzed by this module, albeit by distinct mechanisms. AC2 primarily affects the rate (), whereas BB1 increases the of an ACP-mediated reaction. A third F, AA5, binds to the KS-AT fragment of DEBS Module 2 without altering either parameter; it is phenotypically reminiscent of a previously characterized F, 1B2, shown to principally recognize the N-terminal helical docking domain of DEBS Module 3. Crystal structures of AA5 and 1B2 bound to the KS-AT fragment of Module 2 were solved to 2.70 and 2.65 Å resolution, respectively, and revealed entirely distinct recognition features of the two antibodies. The new tools and insights reported here pave the way toward advancing our understanding of the structure-function relationships of DEBS Module 2, arguably the most well-studied module of an assembly line PKS.

PubMed: 37184546
DOI: 10.1021/acs.biochem.3c00156

Experimental method

X-RAY DIFFRACTION (2.7 Å)