title: Building blocks for automated elucidation of metabolites: machine learning methods for NMR prediction.
abstract: BACKGROUND
  Current efforts in Metabolomics, such as the Human Metabolome Project, collect structures of biological metabolites as well as data for their characterisation, such as spectra for identification of substances and measurements of their concentration. Still, only a fraction of existing metabolites and their spectral fingerprints are known. Computer-Assisted Structure Elucidation (CASE) of biological metabolites will be an important tool to leverage this lack of knowledge. Indispensable for CASE are modules to predict spectra for hypothetical structures. This paper evaluates different statistical and machine learning methods to perform predictions of proton NMR spectra based on data from our open database NMRShiftDB.
  
  
  RESULTS
  A mean absolute error of 0.18 ppm was achieved for the prediction of proton NMR shifts ranging from 0 to 11 ppm. Random forest, J48 decision tree and support vector machines achieved similar overall errors. HOSE codes being a notably simple method achieved a comparatively good result of 0.17 ppm mean absolute error.
  
  
  CONCLUSIONS
  NMR prediction methods applied in the course of this work delivered precise predictions which can serve as a building block for Computer-Assisted Structure Elucidation for biological metabolites.
authors.affiliation: Leibniz Institute of Plant Biochemistry, Department of Stress and Developmental Biology, Weinberg 3, 06120 Halle, Germany. stefhk3@web.de
authors.forename: Stefan
authors.initials: S
authors.lastname: Kuhn
authors.forename: Björn
authors.initials: B
authors.lastname: Egert
authors.forename: Steffen
authors.initials: S
authors.lastname: Neumann
authors.forename: Christoph
authors.initials: C
authors.lastname: Steinbeck
mesh_terms: D000465:Algorithms; D001185:Artificial Intelligence; D016014:Linear Models; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D055432:Metabolomics / Q000379:methods*; D008958:Models, Molecular; D015394:Molecular Structure; D010363:Pattern Recognition, Automated / Q000379:methods*; D025341:Principal Component Analysis / Q000379:methods