5U97

Crystal structure of Co-CAO1 in complex with piceatannol

Summary for 5U97

• Entry DOI: 10.2210/pdb5u97/pdb
• Related: 5U8Z 5U90
• Descriptor: Carotenoid oxygenase 1, COBALT (II) ION, PICEATANNOL, ... (6 entities in total)
• Functional Keywords: carotenoid, cleavage, oxygenase, beta propeller, dioxygenase, piceatannol, carotenoid oxygenase, oxidoreductase
• Biological source: Neurospora crassa OR74A
• Total number of polymer chains: 4
• Total formula weight: 241392.78

Authors

Sui, X.,Palczewski, K.,Banerjee, S.,Kiser, P.D. (deposition date: 2016-12-15, release date: 2017-05-31, Last modification date: 2023-10-25)

Primary citation

Sui, X.,Weitz, A.C.,Farquhar, E.R.,Badiee, M.,Banerjee, S.,von Lintig, J.,Tochtrop, G.P.,Palczewski, K.,Hendrich, M.P.,Kiser, P.D.
Structure and Spectroscopy of Alkene-Cleaving Dioxygenases Containing an Atypically Coordinated Non-Heme Iron Center.
Biochemistry, 56:2836-2852, 2017

PubMed Abstract: Carotenoid cleavage oxygenases (CCOs) are non-heme iron enzymes that catalyze scission of alkene groups in carotenoids and stilbenoids to form biologically important products. CCOs possess a rare four-His iron center whose resting-state structure and interaction with substrates are incompletely understood. Here, we address this knowledge gap through a comprehensive structural and spectroscopic study of three phyletically diverse CCOs. The crystal structure of a fungal stilbenoid-cleaving CCO, CAO1, reveals strong similarity between its iron center and those of carotenoid-cleaving CCOs, but with a markedly different substrate-binding cleft. These enzymes all possess a five-coordinate high-spin Fe(II) center with resting-state Fe-His bond lengths of ∼2.15 Å. This ligand set generates an iron environment more electropositive than those of other non-heme iron dioxygenases as observed by Mössbauer isomer shifts. Dioxygen (O) does not coordinate iron in the absence of substrate. Substrates bind away (∼4.7 Å) from the iron and have little impact on its electronic structure, thus excluding coordination-triggered O binding. However, substrate binding does perturb the spectral properties of CCO Fe-NO derivatives, indicating proximate organic substrate and O-binding sites, which might influence Fe-O interactions. Together, these data provide a robust description of the CCO iron center and its interactions with substrates and substrate mimetics that illuminates commonalities as well as subtle and profound structural differences within the CCO family.

PubMed: 28493664
DOI: 10.1021/acs.biochem.7b00251

Experimental method

X-RAY DIFFRACTION (1.85 Å)