It definitely looks like a circuit trace. It would be almost impossible to determine what it is used for. Best guess is that the PCIe slot next to it will have troubles. But it COULD be for anything -- USB port, Audio, SATA, anything.
Will the motherboard work? Maybe. Could you damage other components? Maybe. If that is a ground -- trace it to see if it connects to a place with a mounting screw, then you PROBABLY could use the motherboard. I probably wouldn't risk it.