Dynamic elements govern the catalytic activity of CapE, a capsular polysaccharide‐synthesizing enzyme from Staphylococcus aureus. Issue 23 (21st October 2013)

• Record Type: Journal Article
• Authors: Miyafusa, Takamitsu; Caaveiro, Jose M.M.; Tanaka, Yoshikazu; Tsumoto, Kouhei
• Is Part Of: FEBS letters. Volume 587:Issue 23(2013)
• Page Start: 3824
• Page End: 3830
• Publication Date: 2013-10-21
• Subjects: Pathogenic bacterium -- Capsular polysaccharide -- X-ray crystallography -- Conformational change -- SDR enzyme -- UDP-sugar -- Staphylococcus aureus -- CP -- capsular polysaccharide -- SDR -- short-chain dehydrogenase/reductase -- SEC -- size-exclusion chromatography -- HPLC -- high performance liquid chromatography -- UDP-arabino-sugar -- UDP-2-acetamido-2, 6-deoxy-α-l-arabino-4-hexulose -- UDP-xylo-sugar -- UDP-2-acetamido-2, 6-deoxy-α-d-xylo-4-hexulose; Biochemistry -- Periodicals; Biophysics -- Periodicals; Molecular biology -- Periodicals; Biochimie -- Périodiques; Biochemistry; Biophysics; Molecular biology; Periodicals; 572.05
• DOI: 10.1016/j.febslet.2013.10.009
• Languages: English
• ISSNs: 0014-5793

Abstract

Abstract : CapE is an essential enzyme for the synthesis of capsular polysaccharide (CP) of pathogenic strains of Staphylococcus aureus . Herein we demonstrate that CapE is a 5‐inverting 4, 6‐dehydratase enzyme. However, in the absence of downstream enzymes, CapE catalyzes an additional reaction (5‐back‐epimerization) affording a by‐product under thermodynamic control. Single‐crystal X‐ray crystallography was employed to identify the structure of the by‐product. The structural analysis reveals a network of coordinated motions away from the active site governing the enzymatic activity of CapE. A second dynamic element (the latch) regulates the enzymatic chemoselectivity. The validity of these mechanisms was evaluated by site‐directed mutagenesis. Abstract : CapE is essential for the synthesis of the capsular polysaccharide of S. aureus . CapE catalyzes two sequential reactions, but the second one yields a by‐product. X‐ray crystallography reveals the identity of the by‐product. Dynamic regions of CapE govern the yield of product with respect to by‐product.