title: Protein acyltransferase function of purified calreticulin. Part 1: characterization of propionylation of protein utilizing propoxycoumarin as the propionyl group donor.
abstract: We have earlier reported that an endoplasmic reticulum luminal protein calreticulin (CR) mediated the acetylation of certain receptor proteins such as glutathione S-transferase (GST) by polyphenolic acetates, leading to irreversible inhibition. This function of calreticulin was termed calreticulin transacetylase. In this communication, we have demonstrated for the first time the ability of the purified recombinant calreticulin of a parasitic nematode Haemonchus contortus to transfer propionyl group from 7,8-Dipropoxy-4-methylcoumarin (DPMC) to recombinant Schistosoma japonicum glutathione S-transferase (rGST). Calreticulin transacetylase exhibited hyperbolic kinetics and yielded K(m) (140 microM) and V(max) (105 units) when the concentration of DPMC was varied keeping the concentration of rGST constant. rGST thus propionylated was found to positively interact with anti-acetyl lysine antibody. Also, the nanoscale LC-MS/MS analysis identified the propionylation sites on three lysine residues: Lys-11, -180 and -181 of rGST. These results highlight the transacylase function of calreticulin (CRTAase).
authors.affiliation: Department of Biochemistry, V.P. Chest Institute; Department of Chemistry, University of Delhi, Delhi 110007, India.
authors.forename: Prabhjot
authors.initials: P
authors.lastname: Singh
authors.forename: Prija
authors.initials: P
authors.lastname: Ponnan
authors.forename: Shibu
authors.initials: S
authors.lastname: Krishnan
authors.forename: Tapesh Kumar
authors.initials: TK
authors.lastname: Tyagi
authors.forename: Nivedita
authors.initials: N
authors.lastname: Priya
authors.forename: Seema
authors.initials: S
authors.lastname: Bansal
authors.forename: Domenica
authors.initials: D
authors.lastname: Scumaci
authors.forename: Marco
authors.initials: M
authors.lastname: Gaspari
authors.forename: Giovanni
authors.initials: G
authors.lastname: Cuda
authors.forename: Paritosh
authors.initials: P
authors.lastname: Joshi
authors.forename: Jasvinder Kaur
authors.initials: JK
authors.lastname: Gambhir
authors.forename: Daman
authors.initials: D
authors.lastname: Saluja
authors.forename: Ashok Kumar
authors.initials: AK
authors.lastname: Prasad
authors.forename: Luciano
authors.initials: L
authors.lastname: Saso
authors.forename: Ramesh Chandra
authors.initials: RC
authors.lastname: Rastogi
authors.forename: Virinder Singh
authors.initials: VS
authors.lastname: Parmar
authors.forename: Hanumantharao Guru
authors.initials: HG
authors.lastname: Raj
mesh_terms: D000123:Acetyltransferases / Q000378:metabolism*; D000818:Animals; D037282:Calreticulin / Q000302:isolation & purification* / Q000378:metabolism*; D003374:Coumarins / Q000737:chemistry* / Q000378:metabolism*; D006189:Haemonchus / Q000378:metabolism; D007700:Kinetics; D011422:Propionates / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism
chemical_list: C552518:7,8-dipropoxy-4-methylcoumarin; D037282:Calreticulin; D003374:Coumarins; D011422:Propionates; D011994:Recombinant Proteins; D000123:Acetyltransferases; C029658:propionic acid