#! perl -slw
use strict;

my $bigstring="MNRIYSLRYSAVARGFIAVSEFARKCVHKSVRRLCFPVLLLIPVLFSAGSLAGTVNNELGYQLFRDFAENKGMFRPGATNIAIYNKQGEFVGTLDKAAMPDFSAVDSEIGVATLINPQYIASVKHNGGYTNVSFGDGENRYNIVDRNNAPSLDFHAPRLDKLVTEVAPTAVTAQGAVAGAYLDKERYPVFYRLGSGTQYIKDSNGQLTKMGGAYSWLTGGTVGSLSSYQNGEMISTSSGLVFDYKLNGAMPIYGEAGDSGSPLFAFDTVQNKWVLVGVLTAGNGAGGRGNNWAVIPLDFIGQKFNEDNDAPVTFRTSEGGALEWSFNSSTGAGALTQGTTTYAMHGQQGNDLNAGKNLIFQGQNGQINLKDSVSQGAGSLTFRDNYTVTTSNGSTWTGAGIVVDNGVSVNWQVNGVKGDNLHKIGEGTLTVQGTGINEGGLKVGDGKVVLNQQADNKGQVQAFSSVNIASGRPTVVLTDERQVNPDTVSWGYRGGTLDVNGNSLTFHQLKAADYGAVLANNVDKRATITLDYALRADKVALNGWSESGKGTAGNLYKYNNPYTNTTDYFILKQSTYGYFPTDQSSNATWEFVGHSQGDAQKLVADRFNTAGYLFHGQLKGNLNVDNRLPEGVTGALVMDGAADISGTFTQENGRLTLQGHPVIHAYNTQSVADKLAASGDHSVLTQPTSFSQEDWENRSFTFDRLSLKNTDFGLGRNATLNTTIQADNSSVTLGDSRVFIDKNDGQGTAFTLEEGTSVATKDADKSVFNGTVNLDNQSVLNINDIFNGGIQANNSTVNISSDSAVLGNSTLTSTALNLNKGANALASQSFVSDGPVNISDATLSLNSRPDEVSHTLLPVYDYAGSWNLKGDDARLNVGPYSMLSGNINVQDKGTVTLGGEGELSPDLTLQNQMLYSLFNGYRNIWSGSLNAPDATVSMTDTQWSMNGNSTAGNMKLNRTIVGFNGGTSPFTTLTTDNLDAVQSAFVMRTDLNKADKLVINKSATGHDNSIWVNFLKKPSNKDTLDIPLVSAPEATADNLFRASTRVVGFSDVTPILSVRKEDGKKEWVLDGYQVARNDGQGKAAATFMHISYNNFITEVNNLNKRMGDLRDINGEAGTWVRLLNGSGSADGGFTDHYTLLQMGADRKHELGSMDLFTGVMATYTDTDASADLYSGKTKSWGGGFYASGLFRSGAYFDVIAKYIHNENKYDLNFAGAGKQNFRSHSLYAGAEVGYRYHLTDTTFVEPQAELVWGRLQGQTFNWNDSGMDVSMRRNSVNPLVGRTGVVSGKTFSGKDWSLTARAGLHYEFDLTDSADVHLKDAAGEHQINGRKDSRMLYGVGLNARFGDNTRLGLEVERSAFGKYNTDDAINANIRYSF";
my $smallstring="GTMARNDGQGKAAATFMHISYNNFITEVDNLNKRMGDLRDINGEAGTWVRLLNGSGSADGGFTDHYTLLQMGADRKHELGSMDLFTGVMATYTDTDASADLYSGKTKSWGGGFYASGLFRSGAYFDVIAKYIHNENKYDLNFAGAGKQNFRSHSLYAGAEVGYRYHLTDTTFVEPQAELVWGRLQGQTFNWNDSGMDVSMRRNSVNPLVGRTGVVSGKTFSGKDWSLTARAGLHYEFDLTDSADVHLKDAAGEHQINGRKDSRMLYGVGLNARFGDNTRLGLEVERSAFGKYNTDDAINANIRYSFLE";
my $lenBig = length $bigstring;
my $lenSmall = length $smallstring;

my $o = 0;
WHILE: while( $o < $lenSmall ) {
    my $p;
    for my $l ( reverse 1 .. ( $lenSmall - $o ) ) {
        my $ss = substr( $smallstring, $o, $l );

        if( $p = 1+index( $bigstring, $ss ) ) {
            print "Found '$ss'($o:$l) at $p";
            $o += $l;
            next WHILE;
        }
    }
    ++$o;
}

##</code><code>##

C:\test>1070240.pl
Found 'GT'(0:2) at 53
Found 'MA'(2:2) at 1160
Found 'RNDGQGKAAATFMHISYNNFITEV'(4:24) at 1076
Found 'DNL'(28:3) at 419
Found 'NKRMGDLRDINGEAGTWVRLLNGSGSADGGFTDHYTLLQMGADRKHELGSMDLFTGVMATYTDTDASADLYSGKTKSWGGGFYASGLFRSGAYFDVIAKYIHNENKYDLNFAGAGKQNFRSHSLYAGAEVGYRYHLTDTTFVEPQAELVWGRLQGQTFNWNDSGMDVSMRRNSVNPLVGRTGVVSGKTFSGKDWSLTARAGLHYEFDLTDSADVHLKDAAGEHQINGRKDSRMLYGVGLNARFGDNTRLGLEVERSAFGKYNTDDAINANIRYSF'(31:275) at 1103
Found 'LE'(306:2) at 322