LISÄTIETOA BORRELIABAKTEERISTA

[Bb]

Lähettäjä: Soijuv Lähetetty: 21.2.2006 15:55

Useat borrelioosin aiheuttamat ongelmat koskettavat hermostoa. Tästä syystä lähdettiin tutkimaan tuottavatko spirokeetat toksiineja jotka häiritsevät hermoston normaalia toimintaa. Tutkimuksissa löydettiin botuliinin tyyppinen toksiini. Seuraavalta sivulta löytyy paljon muutakin mielenkiintoista tietoa borreliabakteerista yms:


http://www.townsendletter.com/FebMar2006/lyme0206.htm

Lyme Disease Toxin
Because many of the symptoms of Lyme disease involve the nervous system, it
was speculated that the spirochete produced a toxin that disrupted normal nerve function. Through the use of DNA manipulations and a database of known protein toxin DNA sequences, a match was made with a selected Borrelia burgdorferi (Bb) gene and a specific toxin in the database. Protein generated from this cloned Bb gene was examined biochemically and found to have characteristics similar to that of botulinum, the toxin of Clostridium botulinum, a zinc endoproteinase.1

The toxin from Bb belongs to a family of toxic proteins known as "zinc endoproteinases" or metalloproteases, and includes the toxin from the organism causing tetanus as well as those from many other well-known infectious diseases. The structures of this family of toxins are all very similar, as determined by x-ray crystal analysis.2 They all contain zinc and perform the same proteolytic function, namely, cleaving the chemical (covalent) bond between two specific amino acids in a particular protein found in nerve cells.3 The substrate for this enzyme is very large, implying that any inhibitor of enzyme activity blocking the entry of the substrate into the active site must also be very large.

One reason for learning the structure of the toxin (including the active site) is to determine the geometry of this site, the exact positions of the atoms that bind other atoms in the substrate. Knowing the arrangement of these atoms permits the development of inhibitors of the toxin, substances that compete with the normal substrate for active site occupancy.4

Action of Toxin
The action of botulinum (as well as the toxin from the Lyme spirochete) is to prevent, through its action as a proteolytic enzyme, the release of the neurotransmitter acetylcholine. Nerve endings may be associated with other nerves or muscles (the neuromuscular junction). To understand this mechanism in greater detail, consider the basic principles of nerve physiology described below.