Actually I want to build a homology model of a human homotrimeric protein from a FASTA sequences. After BLAST I got a template which is 91% identical but it is originated from Mouse organism. and it is cryo EM structure.

From there, I build a single monomeric chain of that human protein by Homology modelling. But it doesn't contain any biological assembly or asymmetric unit. So that, i am unable to build its trimeric structure. so, can you help me in two sections;

1) how to build its homotrimeric structure?

2) is there any way to generate the biological assembly coordinates from homology protein?

Thanks in advance.

Best regards.