use strict;
use warnings;
use List::MoreUtils qw(natatime);

my $line = '1 AC2 34 TRP A 6 ALA A 7 ILE A 14 GLY A 15';
my @tokens = split /\s+/, $line;
my $it = natatime(3, @tokens);
while (my @vals = $it->()) {
    print "@vals\n";
}