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The crystal structure of AjiA1 reveals a novel structural motion mechanism in the adenylate‐forming enzyme family
Author(s) -
de Paiva Fernanda C. R.,
Chan Karen,
Samborskyy Markiyan,
Silber Ariel M.,
Leadlay Peter F.,
Dias Marcio V. B.
Publication year - 2020
Publication title -
acta crystallographica section d
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.374
H-Index - 138
ISSN - 2059-7983
DOI - 10.1107/s2059798320013431
Subject(s) - benzoxazole , enzyme , adenylate kinase , stereochemistry , chemistry , hydrolase , substrate (aquarium) , molecule , biochemistry , biology , ecology , organic chemistry
Adenylate‐forming enzymes (AFEs) are a mechanistic superfamily of proteins that are involved in many cellular roles. In the biosynthesis of benzoxazole antibiotics, an AFE has been reported to play a key role in the condensation of cyclic molecules. In the biosynthetic gene cluster for the benzoxazole AJI9561, AjiA1 catalyzes the condensation of two 3‐hydroxyanthranilic acid (3‐HAA) molecules using ATP as a co‐substrate. Here, the enzymatic activity of AjiA1 is reported together with a structural analysis of its apo form. The structure of AjiA1 was solved at 2.0 Å resolution and shows a conserved fold with other AFE family members. AjiA1 exhibits activity in the presence of 3‐HAA ( K m = 77.86 ± 28.36, k cat = 0.04 ± 0.004) and also with the alternative substrate 3‐hydroxybenzoic acid (3‐HBA; K m = 22.12 ± 31.35, k cat = 0.08 ± 0.005). The structure of AjiA1 in the apo form also reveals crucial conformational changes that occur during the catalytic cycle of this enzyme which have not been described for any other AFE member. Consequently, the results shown here provide insights into this protein family and a new subgroup is proposed for enzymes that are involved in benzoxazole‐ring formation.