hiv & prions

[Joao Vasconcelos Costa]

Howard R. Olson wrote:
> 
>           Sometime in September of 1986 there was an article about a sequence
> similarity of the Hamster scrapie prion in Nature. There was supposedly a
> "convergence" between the Reverse Transcriptase of HIV and an anlogous gene
> in the prion. Has anyone heard anything about this. Prusiner send a
> really uptight letter to Nature a few weeks later. Where there is smoke there
> is probably fire......

There is no "analogous gene" in prions!

The following is a search for homology (programa BestFit, Wisconsin
package) between the scrapie prion protein PrP and the HIV1 precursor
of the reverse transcriptase:

 prio_sheep.sw x pol_hv1mn.sw April 22, 1996 09:57  ..

                  .         .         .         .         .
       1 MVKSHIGSWILVLFVAMWSDVGLCKKRPKPGGGWNTGGSRYPGQGSPGGN 50
         . .|.:.| |:  :: ....| |.. .:..| | |....:.   .|:| .
     670 KSESELVSQIIEQLI.KKEKVYLAWVPAHKGIGGNEQVDKL...VSAGIR 715
                  .         .         .         .         .
      51 RYPPQGGGGWGQPH...........GGGWGQPHGGGWGQPHGGGWGQPHG 89
         :    :| :.:|..           ::::. |. .:.: . :.:..| .|
     716 KVLFLDGIDKAQEDHEKYHSNWRAMASDFNLPPIVAKEIVASCDKCQLKG 765
                  .         .         .         .         .
      90 GGGWGQGGSHSQW......NKPSKPKTNMKHVAGAAAAGAVVGGLGG... 130
         ::  ||.:: ..       : .:|.     |||::  .:.|:.: .|   
     766 EAMHGQVDCSPGIWQLDCTHLEGKVILVAVHVASGYIEAEVIPAETGQET 815
                  .         .         .         .         .
     131 ..YMLGSAMSRPLIHFGNDYEDRYYRENM...YRYP.............. 161
           ::|  | .:|:  : .| :..: ...:   :::.              
     816 AYFLLKLAGRWPVKTIHTDNGPNFTSTTVKAACWWTGIKQEFGIPYNPQS 865
                  .         .         .         .         .
     162 .......NQVYYRPVDRYSNQNNFVHDCVNITV......KQHTVTTTTKG 198
                |. . : ::. .:|.: :. .|.:.|      :. .:.. . |
     866 QGVIESMNKELKKIIGQVRDQAEHLKRAVQMAVFIHNFKRKGGIGGYSAG 915
                  .         .         .         .         .
     199 ENF.....TETDIKIMERVVEQM.CITQYQRESQAYYQRGASVILFSSPP 242
         |.:     |:.:.| ::: :..:  :  | |:|.. . :|:. :|:.:..
     916 ERIVGIIATDIQTKELQKQITKIQNFRVYYRDSRDPLWKGPAKLLWKGEG 965
                  .    
     243 VILLISFLIFLIVG 256
         .::: .   : :|.
     966 AVVIQDNNDIKVVP 979

You can find this degree of "homology" between many unrelated proteins.

Joao
 
-- 
*****   JOAO VASCONCELOS COSTA, MD, PhD
*****   Instituto Gulbenkian de Ciencia - Oeiras, Portugal
*****   mailto:jcosta at pen.gulbenkian.pt
*****   http://www.pen.gulbenkian.pt/v2/jvc.html