color by Residue
color by Chain
Ribbon
Backbone
ribbon Cartoonize
show Water

Controls:
rotate: click+drag
zoom: scroll
translate: alt+click+drag

Canvas is matched to your browser window. ChemDoodle Web Component library is used to show 3D PDB files. There are more options but I'm not an expert. PDB files are compressed on fly by server.
Open Source molecule viewers     updated 21 Apr 2012