app.py

import gradio as gr

def update(name):
    return f"Welcome to Gradio, {name}!"

demo = gr.Blocks()

with demo:
    gr.Markdown("# Metal3D")
    with gr.Row():
        inp = gr.Textbox(placeholder="2CBA", label="PDB or Uniprot code")
        file  = gr.File(file_count=1, label="Upload a PDB file")
        out = gr.Textbox()
    btn = gr.Button("Run Metal3D")
    btn.click(fn=update, inputs=inp, outputs=out)

demo.launch()