Are you asking for Mayo specifically, or generally? My impression is that each division at Mayo has a salary range (so those requiring fellowships have a different range than those that do not) and as a new grad, you start at Step 1 (not sure if you have experience as an attending in your field if you start out higher on the ladder or not).
Elsewhere, salary offers depend on a lot of things, including experience, degrees, location you're working, etc. One of my junior faculty got an extra 3K per year for having an MPH.