JModel Test suggested HKY+G and TPM3uf+I+G as best fit models. I used the following set up for HKY+G model block preparation in MrBayes and it worked perfectly-

Begin mrbayes;

set autoclose=no nowarn=yes;

lset nst=2; lset rates=gamma;

prset tratiopr=fixed(4.99);

prset statefreqpr=fixed(0.2135,0.2819,0.2094,0.2953);

prset shapepr=fixed(0.1610);

mcmc ngen=1000000 nchains=4 relburnin=yes burninfrac=0.25 printfreq=1000 samplefreq=1000 savebrlens=yes;

mcmc;

sumt;

end;

But not sure how to set the TPM3uf+I+G model in MrBayes. Any suggestion would be highly appreciated.