Facile synthesis of SAM–peptide conjugates through alkyl linkers targeting protein N-terminal methyltransferase 1

Abstract

We report the first chemical synthesis of SAM–peptide conjugates through alkyl linkers to prepare bisubstrate analogs for protein methyltransferases. We demonstrate its application by developing a series of bisubstrate inhibitors for protein N-terminal methyltransferase 1 and the most potent one exhibits a Ki value of 310 ± 55 nM.

Chemical Biology of Protein N‐Terminal Methyltransferases

“…Compound NAM-TZ-SPKRIA (IC 50 = (0.81 AE 0.13) mm)c ontains at riazole linker andi ncorporatesa SPKRIA peptide derived from the Nterminus of RCC1, whereas NAM-C3-GPRRRS (IC 50 = 0.94 AE 0.16 mm)l inks aG PKRRSp eptide derived from CENP-A through ap ropylene group. [57,58] NAM-TZ-SPKRIAs howedl ess than 50 %i nhibition against PKMT G9a and PRMT1at50mm. [57] NAM-C3-GPRRRS showednosignificant inhibition at 30 mm against either G9a or PRMT1.…”

“…NAM‐TZ‐SPKRIA showed less than 50 % inhibition against PKMT G9a and PRMT1 at 50 μ m . NAM‐C3‐GPRRRS showed no significant inhibition at 30 μ m against either G9a or PRMT1 . Kinetic analysis revealed that inhibitor NAM‐TZ‐SPKRIA engaged with both substrate binding sites .…”

“…Bisubstrate analogues that simultaneously target both binding sites are proven to be an effective strategy to obtain potent and selective inhibitors for many enzymes with two binding sites . Because NTMT1 forms a ternary complex during catalysis, a bisubstrate strategy has been applied to design and synthesize bisubstrate inhibitors by covalently linking a SAM analogue with a peptide substrate to mimic the transition state . NTMT1 bisubstrate inhibitors contain three components: an N ‐adenosyl‐ l ‐methionine (NAM) that replaces the sulfonium ion of SAM with a nitrogen atom, a hexapeptide derived from the N‐terminal sequence of NTMT1 substrate, and a linker (Scheme ).…”

“…NTMT1 bisubstrate inhibitors contain three components: an N ‐adenosyl‐ l ‐methionine (NAM) that replaces the sulfonium ion of SAM with a nitrogen atom, a hexapeptide derived from the N‐terminal sequence of NTMT1 substrate, and a linker (Scheme ). Compound NAM‐TZ‐SPKRIA (IC 50 =(0.81±0.13) μ m ) contains a triazole linker and incorporates a SPKRIA peptide derived from the N terminus of RCC1, whereas NAM‐C3‐GPRRRS (IC 50 =0.94±0.16 μ m ) links a GPKRRS peptide derived from CENP‐A through a propylene group . NAM‐TZ‐SPKRIA showed less than 50 % inhibition against PKMT G9a and PRMT1 at 50 μ m .…”

“…[54][55][56] Because NTMT1 forms at ernary complex during catalysis,abisubstrate strategy has been appliedt od esign and synthesize bisubstrate inhibitors by covalently linking aS AM analogue with ap eptide substrate to mimic the transition state. [57,58] NTMT1 bisubstrate inhibitors contain three components:a nN-adenosyl-l-methionine (NAM)t hat replaces the sulfonium iono fS AM with an itrogen atom, ah exapeptide derived from the N-terminal sequence of NTMT1 substrate, and al inker (Scheme 2). Compound NAM-TZ-SPKRIA (IC 50 = (0.81 AE 0.13) mm)c ontains at riazole linker andi ncorporatesa SPKRIA peptide derived from the Nterminus of RCC1, whereas NAM-C3-GPRRRS (IC 50 = 0.94 AE 0.16 mm)l inks aG PKRRSp eptide derived from CENP-A through ap ropylene group.…”