That is not a deadlift.
Here's my suggestion - reduce the weight to around 300 pounds. Do reps of 8-10, focussing on proper form (ask someone to show you how to properly deadlift). This will help you build muscle, reduce the risk of you getting an injury, and ultimately, with proper training you will be able to do a proper deadlift with a bigger weights. (Also suggest you warm up to deadlifts and exercize your lower back with hyperextensions, and/or goodmornings bendovers with a bar across your back, again focussing on technique and keeping your back straight.