6XA3

Structure of the ligand free P450 monooxygenase TamI

Summary for 6XA3

• Entry DOI: 10.2210/pdb6xa3/pdb
• Related: 6XA2
• Descriptor: TamI, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• Functional Keywords: p450, monooxygenase, oxidoreductase
• Biological source: Streptomyces sp. 307-9
• Total number of polymer chains: 1
• Total formula weight: 49706.09

Authors

Newmister, S.A.,Srivastava, K.R.,Espinoza, R.V.,Haatveit, K.C.,Khatri, Y.,Martini, R.M.,Garcia-Borras, M.,Podust, L.M.,Houk, K.N.,Sherman, D.H. (deposition date: 2020-06-03, release date: 2021-06-23, Last modification date: 2023-10-18)

Primary citation

Newmister, S.A.,Srivastava, K.R.,Espinoza, R.V.,Haatveit, K.C.,Khatri, Y.,Martini, R.M.,Garcia-Borras, M.,Podust, L.M.,Houk, K.N.,Sherman, D.H.
Molecular Basis of Iterative C─H Oxidation by TamI, a Multifunctional P450 monooxygenase from the Tirandamycin Biosynthetic Pathway.
Acs Catalysis, 10:13445-13454, 2020

PubMed Abstract: Biocatalysis offers an expanding and powerful strategy to construct and diversify complex molecules by C─H bond functionalization. Due to their high selectivity, enzymes have become an essential tool for C─H bond functionalization and offer complementary reactivity to small-molecule catalysts. Hemoproteins, particularly cytochromes P450, have proven effective for selective oxidation of unactivated C─H bonds. Previously, we reported the characterization of an oxidative tailoring cascade in which TamI, a multifunctional P450 functions co-dependently with the TamL flavoprotein to catalyze regio- and stereoselective hydroxylations and epoxidation to yield tirandamycin A and tirandamycin B. TamI follows a defined order including 1) C10 hydroxylation, 2) C11/C12 epoxidation, and 3) C18 hydroxylation. Here we present a structural, biochemical, and computational investigation of TamI to understand the molecular basis of its substrate binding, diverse reactivity, and specific reaction sequence. The crystal structure of TamI in complex with tirandamycin C together with molecular dynamics simulations and targeted mutagenesis suggest that hydrophobic interactions with the polyene chain of its natural substrate are critical for molecular recognition. QM calculations and molecular dynamics simulations of TamI with variant substrates provided detailed information on the molecular basis of sequential reactivity, and pattern of regio- and stereo-selectivity in catalyzing the three-step oxidative cascade.

PubMed: 33569241
DOI: 10.1021/acscatal.0c03248

Experimental method

X-RAY DIFFRACTION (2.96 Å)