Protein acyltransferase function of purified calreticulin. Part 1: characterization of propionylation of protein utilizing propoxycoumarin as the propionyl group donor.
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).
Singh
Prabhjot
P
Department of Biochemistry, V.P. Chest Institute; Department of Chemistry, University of Delhi, Delhi 110007, India.
Ponnan
Prija
P
Krishnan
Shibu
S
Tyagi
Tapesh Kumar
TK
Priya
Nivedita
N
Bansal
Seema
S
Scumaci
Domenica
D
Gaspari
Marco
M
Cuda
Giovanni
G
Joshi
Paritosh
P
Gambhir
Jasvinder Kaur
JK
Saluja
Daman
D
Prasad
Ashok Kumar
AK
Saso
Luciano
L
Rastogi
Ramesh Chandra
RC
Parmar
Virinder Singh
VS
Raj
Hanumantharao Guru
HG
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
C552518:7,8-dipropoxy-4-methylcoumarin; D037282:Calreticulin; D003374:Coumarins; D011422:Propionates; D011994:Recombinant Proteins; D000123:Acetyltransferases; C029658:propionic acid