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Characterization of covalently inhibited extracellular lipase from Streptomyces rimosus by matrix-assisted laser desorption/ionization time-of-flight and matrix-assisted laser desorption/ionization quadrupole ion trap reflectron time-of-flight mass spectrometry: localization of the active site serine.
J Mass Spectrom. 2004 Dec; 39(12):1474-83.JM

Abstract

A chemical modification approach combined with matrix-assisted laser desorption/ionization (MALDI) mass spectrometry was used to identify the active site serine residue of an extracellular lipase from Streptomyces rimosus R6-554W. The lipase, purified from a high-level overexpressing strain, was covalently modified by incubation with 3,4-dichloroisocoumarin, a general mechanism-based serine protease inhibitor. MALDI time-of-flight (TOF) mass spectrometry was used to probe the nature of the intact inhibitor-modified lipase and to clarify the mechanism of lipase inhibition by 3,4-dichloroisocoumarin. The stoichiometry of the inhibition reaction revealed that specifically one molecule of inhibitor was bound to the lipase. The MALDI matrix 2,6-dihydroxyacetophenone facilitated the formation of highly abundant [M + 2H](2+) ions with good resolution compared to other matrices in a linear TOF instrument. This allowed the detection of two different inhibitor-modified lipase species. Exact localization of the modified amino acid residue was accomplished by tryptic digestion followed by low-energy collision-induced dissociation peptide sequencing of the detected 2-(carboxychloromethyl)benzoylated peptide by means of a MALDI quadrupole ion trap reflectron TOF instrument. The high sequence coverage obtained by this approach allowed the confirmation of the site specificity of the inhibition reaction and the unambiguous identification of the serine at position 10 as the nucleophilic amino acid residue in the active site of the enzyme. This result is in agreement with the previously obtained data from multiple sequence alignment of S. rimosus lipase with different esterases, which indicated that this enzyme exhibits a characteristic Gly-Asp-Ser-(Leu) motif located close to the N-terminus and is harboring the catalytically active serine residue. Therefore, this study experimentally proves the classification of the S. rimosus lipase as GDS(L) lipolytic enzyme.

Authors+Show Affiliations

Institute of Chemical Technologies and Analysis, Vienna University of Technology, Getreidemarkt 9/164-IAC, A-1060 Vienna, Austria.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15578758

Citation

Zehl, Martin, et al. "Characterization of Covalently Inhibited Extracellular Lipase From Streptomyces Rimosus By Matrix-assisted Laser Desorption/ionization Time-of-flight and Matrix-assisted Laser Desorption/ionization Quadrupole Ion Trap Reflectron Time-of-flight Mass Spectrometry: Localization of the Active Site Serine." Journal of Mass Spectrometry : JMS, vol. 39, no. 12, 2004, pp. 1474-83.
Zehl M, Lescić I, Abramić M, et al. Characterization of covalently inhibited extracellular lipase from Streptomyces rimosus by matrix-assisted laser desorption/ionization time-of-flight and matrix-assisted laser desorption/ionization quadrupole ion trap reflectron time-of-flight mass spectrometry: localization of the active site serine. J Mass Spectrom. 2004;39(12):1474-83.
Zehl, M., Lescić, I., Abramić, M., Rizzi, A., Kojić-Prodić, B., & Allmaier, G. (2004). Characterization of covalently inhibited extracellular lipase from Streptomyces rimosus by matrix-assisted laser desorption/ionization time-of-flight and matrix-assisted laser desorption/ionization quadrupole ion trap reflectron time-of-flight mass spectrometry: localization of the active site serine. Journal of Mass Spectrometry : JMS, 39(12), 1474-83.
Zehl M, et al. Characterization of Covalently Inhibited Extracellular Lipase From Streptomyces Rimosus By Matrix-assisted Laser Desorption/ionization Time-of-flight and Matrix-assisted Laser Desorption/ionization Quadrupole Ion Trap Reflectron Time-of-flight Mass Spectrometry: Localization of the Active Site Serine. J Mass Spectrom. 2004;39(12):1474-83. PubMed PMID: 15578758.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Characterization of covalently inhibited extracellular lipase from Streptomyces rimosus by matrix-assisted laser desorption/ionization time-of-flight and matrix-assisted laser desorption/ionization quadrupole ion trap reflectron time-of-flight mass spectrometry: localization of the active site serine. AU - Zehl,Martin, AU - Lescić,Ivana, AU - Abramić,Marija, AU - Rizzi,Andreas, AU - Kojić-Prodić,Biserka, AU - Allmaier,Günter, PY - 2004/12/4/pubmed PY - 2005/4/15/medline PY - 2004/12/4/entrez SP - 1474 EP - 83 JF - Journal of mass spectrometry : JMS JO - J Mass Spectrom VL - 39 IS - 12 N2 - A chemical modification approach combined with matrix-assisted laser desorption/ionization (MALDI) mass spectrometry was used to identify the active site serine residue of an extracellular lipase from Streptomyces rimosus R6-554W. The lipase, purified from a high-level overexpressing strain, was covalently modified by incubation with 3,4-dichloroisocoumarin, a general mechanism-based serine protease inhibitor. MALDI time-of-flight (TOF) mass spectrometry was used to probe the nature of the intact inhibitor-modified lipase and to clarify the mechanism of lipase inhibition by 3,4-dichloroisocoumarin. The stoichiometry of the inhibition reaction revealed that specifically one molecule of inhibitor was bound to the lipase. The MALDI matrix 2,6-dihydroxyacetophenone facilitated the formation of highly abundant [M + 2H](2+) ions with good resolution compared to other matrices in a linear TOF instrument. This allowed the detection of two different inhibitor-modified lipase species. Exact localization of the modified amino acid residue was accomplished by tryptic digestion followed by low-energy collision-induced dissociation peptide sequencing of the detected 2-(carboxychloromethyl)benzoylated peptide by means of a MALDI quadrupole ion trap reflectron TOF instrument. The high sequence coverage obtained by this approach allowed the confirmation of the site specificity of the inhibition reaction and the unambiguous identification of the serine at position 10 as the nucleophilic amino acid residue in the active site of the enzyme. This result is in agreement with the previously obtained data from multiple sequence alignment of S. rimosus lipase with different esterases, which indicated that this enzyme exhibits a characteristic Gly-Asp-Ser-(Leu) motif located close to the N-terminus and is harboring the catalytically active serine residue. Therefore, this study experimentally proves the classification of the S. rimosus lipase as GDS(L) lipolytic enzyme. SN - 1076-5174 UR - https://www.unboundmedicine.com/medline/citation/15578758/Characterization_of_covalently_inhibited_extracellular_lipase_from_Streptomyces_rimosus_by_matrix_assisted_laser_desorption/ionization_time_of_flight_and_matrix_assisted_laser_desorption/ionization_quadrupole_ion_trap_reflectron_time_of_flight_mass_spectrometry:_localization_of_the_active_site_serine_ L2 - https://doi.org/10.1002/jms.750 DB - PRIME DP - Unbound Medicine ER -