Multinuclear NMR resonance assignments and the secondary structure of Escherichia coli thioesterase/protease I: A member of a new subclass of lipolytic enzymes

Ta Hsien Lin, Chinpan Chen, Rong Fong Huang, Ya Lin Lee, Jei Fu Shaw, Tai Huang Huang

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

Escherichia coli thioesterase/protease I is a 183 amino acid protein with a molecular mass of 20 500. This protein belongs to a new subclass of lipolytic enzymes of the serine protease superfamily, but with a new GDSLS consensus motif, of which no structure has yet been determined. The protein forms a tetramer at pH values above 6.5 and exists as a monomer at lower pH values. Both monomer and tetramer are catalytically active. From analysis of a set of heteronuclear multidimensional NMR spectra with uniform and specific amino acid labeled protein samples, we have obtained near-complete resonance assignments of the backbone 1H, 13C and 15N nuclei (BMRB databank accession number 4060). The secondary structure of E. coli thioesterase/protease I was further deduced from the consensus chemical shift indices, backbone short- and medium-range NOEs, and amide proton exchange rates. The protein was found to consist of four β-strands and seven α-helices, arranged in alternate order. The four β-strands were shown to form a parallel β-sheet. The topological arrangement of the β-strands of -1x, +2x, +1x appears to resemble that of the core region of the αβ hydrolase superfamily, typically found in common lipases and esterases. However, substantial differences, such as the number of β-strands and the location of the catalytic triad residues, make it difficult to give a definitive classification of the structure of E. coli thioesterase/protease I at present.

Original languageEnglish
Pages (from-to)363-380
Number of pages18
JournalJournal of Biomolecular NMR
Volume11
Issue number4
DOIs
Publication statusPublished - 1998 Jan 1

Keywords

  • Chemical shift indices
  • Heteronuclear triple-resonance NMR
  • Lipase
  • Lipolytic enzyme
  • Resonance assignment

ASJC Scopus subject areas

  • Biochemistry
  • Spectroscopy

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