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Leishmania major biotin protein ligase forms a unique cross‐handshake dimer
Author(s) -
Rajak Manoj Kumar,
Bhatnagar Sonika,
Pandey Shubhant,
Kumar Sunil,
Verma Shalini,
Patel Ashok Kumar,
Sundd Monica
Publication year - 2021
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/s2059798321001418
Subject(s) - biotin , dna ligase , pyruvate carboxylase , biochemistry , acetyl coa carboxylase , dimer , biotinylation , enzyme , chemistry , ubiquitin ligase , biology , ubiquitin , organic chemistry , gene
Biotin protein ligase catalyses the post‐translational modification of biotin carboxyl carrier protein (BCCP) domains, a modification that is crucial for the function of several carboxylases. It is a two‐step process that results in the covalent attachment of biotin to the ϵ‐amino group of a conserved lysine of the BCCP domain of a carboxylase in an ATP‐dependent manner. In Leishmania , three mitochondrial enzymes, acetyl‐CoA carboxylase, methylcrotonyl‐CoA carboxylase and propionyl‐CoA carboxylase, depend on biotinylation for activity. In view of the indispensable role of the biotinylating enzyme in the activation of these carboxylases, crystal structures of L. major biotin protein ligase complexed with biotin and with biotinyl‐5′‐AMP have been solved. L. major biotin protein ligase crystallizes as a unique dimer formed by cross‐handshake interactions of the hinge region of the two monomers formed by partial unfolding of the C‐terminal domain. Interestingly, the substrate (BCCP domain)‐binding site of each monomer is occupied by its own C‐terminal domain in the dimer structure. This was observed in all of the crystals that were obtained, suggesting a closed/inactive conformation of the enzyme. Size‐exclusion chromatography studies carried out using high protein concentrations (0.5 m M ) suggest the formation of a concentration‐dependent dimer that exists in equilibrium with the monomer.