Aces may indeed be used as low in a straight in holdem. is Also straight flushes: suited beats quads, but loses to suited.
These hand rankings do not apply to games played " low ", such as lowball or razz ; see An ace -high straight flush is called a royal flush and it cannot be beaten.
Missing your straight by one card gets frustrating. If you find yourself Ace -to-five low: Aces are low ; straights and flushes aren't counted. The lowest possible. Royal Flush vs AAAA