title: Chemical Shifts to Metabolic Pathways: Identifying Metabolic Pathways Directly from a Single 2D NMR Spectrum.
abstract: Identifying cellular processes in terms of metabolic pathways is one of the avowed goals of metabolomics studies. Currently, this is done after relevant metabolites are identified to allow their mapping onto specific pathways. This task is daunting due to the complex nature of cellular processes and the difficulty in establishing the identity of individual metabolites. We propose here a new method: ChemSMP (Chemical Shifts to Metabolic Pathways), which facilitates rapid analysis by identifying the active metabolic pathways directly from chemical shifts obtained from a single two-dimensional (2D) [(13)C-(1)H] correlation NMR spectrum without the need for identification and assignment of individual metabolites. ChemSMP uses a novel indexing and scoring system comprised of a "uniqueness score" and a "coverage score". Our method is demonstrated on metabolic pathways data from the Small Molecule Pathway Database (SMPDB) and chemical shifts from the Human Metabolome Database (HMDB). Benchmarks show that ChemSMP has a positive prediction rate of >90% in the presence of decluttered data and can sustain the same at 60-70% even in the presence of noise, such as deletions of peaks and chemical shift deviations. The method tested on NMR data acquired for a mixture of 20 amino acids shows a success rate of 93% in correct recovery of pathways. When used on data obtained from the cell lysate of an unexplored oncogenic cell line, it revealed active metabolic pathways responsible for regulating energy homeostasis of cancer cells. Our unique tool is thus expected to significantly enhance analysis of NMR-based metabolomics data by reducing existing impediments.
authors.affiliation: IISc Mathematics Initiative, ‡NMR Research Centre, §Molecular Reproduction, Development and Genetics, ∥Supercomputer Education and Research Centre, and ⊥Solid State and Structural Chemistry Unit, Indian Institute of Science , Bangalore 560012, India.
authors.forename: Abhinav
authors.initials: A
authors.lastname: Dubey
authors.affiliation: IISc Mathematics Initiative, ‡NMR Research Centre, §Molecular Reproduction, Development and Genetics, ∥Supercomputer Education and Research Centre, and ⊥Solid State and Structural Chemistry Unit, Indian Institute of Science , Bangalore 560012, India.
authors.forename: Annapoorni
authors.initials: A
authors.lastname: Rangarajan
authors.affiliation: IISc Mathematics Initiative, ‡NMR Research Centre, §Molecular Reproduction, Development and Genetics, ∥Supercomputer Education and Research Centre, and ⊥Solid State and Structural Chemistry Unit, Indian Institute of Science , Bangalore 560012, India.
authors.forename: Debnath
authors.initials: D
authors.lastname: Pal
authors.affiliation: IISc Mathematics Initiative, ‡NMR Research Centre, §Molecular Reproduction, Development and Genetics, ∥Supercomputer Education and Research Centre, and ⊥Solid State and Structural Chemistry Unit, Indian Institute of Science , Bangalore 560012, India.
authors.forename: Hanudatta S
authors.initials: HS
authors.lastname: Atreya
mesh_terms: D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism; D045744:Cell Line, Tumor; D003903:Deuterium / Q000737:chemistry*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D053858:Metabolic Networks and Pathways; D055432:Metabolomics
chemical_list: D000596:Amino Acids; D003903:Deuterium