You could use PCR based methods such as Splicing by Overlap Extension (SOE-PCR); but you need to make sure there are no frameshifts to get a bifunctional enzyme/ chimeric protein.

These articles may help you,

Article Synthetic fusion protein design and applications

Article Enzyme Fusions in Biocatalysis: Coupling Reactions by Pairing Enzymes

Dear Abhilek!

I recommend my previously work. A fused two different protein, but you can use also to domains. Here is the publication:

Article Heterologous Expression and Purification of Recombinant Proa...

If you need more help, I can help you to design the fuse.

Good work!

Overlap extension is the most straightforward method - just make sure to select the right linker. You can find more information about it in my previous works available on researchgate.

You could use PCR-ligationPCR as described here...

Article PCR-ligation-PCR mutagenesis: A protocol for creating gene f...