It's a fairly typical flamenco chord progression, also found in pop music - the Ventures 'Walk, Don't Run', and the ubiquitous 'Stairway to Heaven' after the guitar solo are but two examples.

Theory-wise it's down to the 'melodic minor scale', which is different 'ascending' and 'descending', unlike the 'harmonic minor' whigh remains the same.

'A melodic minor' runs as follows:
A B C D E F# G# A G F E D C B A

'A harmonic minor', however, is:
A B C D E F G# A G# F E D C B A

I'll stop there, in case we've reached 'information overload'!