Structural and Stereochemical Analysis of a Modular Polyketide Synthase Ketoreductase Domain Required for the Generation of a cis-Alkene

Bonnett, Shilah A.; Whicher, Jonathan R.; Kancharla, Papireddy; Florova, Galina; Smith, Janet L.; Reynolds, Kevin A.

doi:10.1016/j.chembiol.2013.04.014

Cited by 54 publications

(82 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Mutation to W359 of AmpKR2 and the corresponding residue in EryKR1 does affect the stereospecificity of KR domains (Baerga-Ortiz et al, 2006; Zheng et al, 2010). The “W” motifs of PlmKR1 and AmpKR11 are buried more deeply and may not form hydrogen bonds with the pantetheine handles directly (Bonnett et al, 2013; Zheng et al, 2013). The ternary structure of a B-type KR complexed with a substrate is still unavailable.…”

Section: Discussionmentioning

confidence: 99%

Substrate-bound structures of a ketoreductase from amphotericin modular polyketide synthase

Liu

Yuan

et al. 2018

Journal of Structural Biology

View full text Add to dashboard Cite

Ketoreductase (KR) domains of modular polyketide synthases (PKSs) control the stereochemistry of C2 methyl and C3 hydroxyl substituents of polyketide intermediates. To understand the molecular basis of stereocontrol exerted by KRs, the crystal structure of a KR from the second module of the amphotericin PKS (AmpKR2) complexed with NADP+ and 2-methyl-3-oxopentanoyl-pantetheine was solved. This first ternary structure provides direct evidence to the hypothesis that a substrate enters into the active site of an A-type KR from the side opposite the coenzyme to generate an L-hydroxyl substituent. A comparison with the ternary complex of a G355T/Q364H mutant sheds light on the structural basis for stereospecificity toward the substrate C2 methyl substituent. Functional assays suggest the pantetheine handle shows obvious influence on the catalytic efficiency and the stereochemical outcome. Together, these findings extend our current understanding of the stereo-chemical control of PKS KR domains.

show abstract

Section: Discussionmentioning

confidence: 99%

Substrate-bound structures of a ketoreductase from amphotericin modular polyketide synthase

Liu

Yuan

et al. 2018

Journal of Structural Biology

View full text Add to dashboard Cite

show abstract

“…The direction from which a β-keto substrate enters the KR active site is thought to establish the chirality of the β-hydroxy KR product [56], and the ACP is in a perfect position to introduce its substrate under the lid into the active site from either direction. Two sequence motifs in PKS KR domains are strongly correlated with specific stereochemical outcomes [57] through a mechanism that is not apparent in structures of excised KR domains but may involve blocking access from one direction or the other after cofactor binding [58]. …”

Section: Overall Architecturementioning

confidence: 99%

Architecture of the polyketide synthase module: surprises from electron cryo-microscopy

Smith

Skiniotis

Sherman

2015

Current Opinion in Structural Biology

View full text Add to dashboard Cite

Modular polyketide synthases produce a vast array of bioactive molecules that are the basis of many highly valued pharmaceuticals. The biosynthesis of these compounds is based on ordered assembly lines of multi-domain modules, each extending and modifying a specific chain-elongation intermediate before transfer to the next module for further processing. The first 3D structures of a full polyketide synthase module in different functional states were obtained recently by electron cryo-microscopy. The unexpected module architecture revealed a striking evolutionary divergence of the polyketide synthase compared to its metazoan fatty acid synthase homolog, as well as remarkable conformational rearrangements dependent on its biochemical state during the full catalytic cycle. The design and dynamics of the module are highly optimized for both catalysis and fidelity in the construction of complex, biologically active natural products.

show abstract

“…Subsequent studies both in vitro 51 and in vivo 52 on KRs sourced from multiple PKSs have conclusively demonstrated their intrinsic epimerase activity. Despite the resolution of seven KR structures [29][30][31][32][33][34][35] , however, multiple aspects of the mechanism remain unclear. For example, although specific active site sequence motifs correlate well with the direction of ketoreduction (whether A-or B-type) 53,54 , how and whether these residues participate in guiding the substrate into one side or the other of the active site has been unclear.…”

Section: The Dissection Approach To Studying Functional Domainsmentioning

confidence: 99%

The structural biology of biosynthetic megaenzymes

Weissman¹

2015

Nat Chem Biol

177

165

View full text Add to dashboard Cite

The modular polyketide synthases (PKSs) and nonribosomal peptide synthetases (NRPSs) are among the largest and most complicated enzymes in nature. In these biosynthetic systems, independently folding protein domains, which are organized into units called 'modules', operate in assembly-line fashion to construct polymeric chains and tailor their functionalities. Products of PKSs and NRPSs include a number of blockbuster medicines, and this has motivated researchers to understand how they operate so that they can be modified by genetic engineering. Beginning in the 1990s, structural biology has provided a number of key insights. The emerging picture is one of remarkable dynamics and conformational programming in which the chemical states of individual catalytic domains are communicated to the others, configuring the modules for the next stage in the biosynthesis. This unexpected level of complexity most likely accounts for the low success rate of empirical genetic engineering experiments and suggests ways forward for productive megaenzyme synthetic biology.

show abstract

Structural and Stereochemical Analysis of a Modular Polyketide Synthase Ketoreductase Domain Required for the Generation of a cis-Alkene

Cited by 54 publications

References 40 publications

Substrate-bound structures of a ketoreductase from amphotericin modular polyketide synthase

Substrate-bound structures of a ketoreductase from amphotericin modular polyketide synthase

Architecture of the polyketide synthase module: surprises from electron cryo-microscopy

The structural biology of biosynthetic megaenzymes

Contact Info

Product

Resources

About