Molecular cloning and functional expression of a novel Helicobacter pylori alpha-1,4 fucosyltransferase.
Helicobacter pylori is an important human pathogen which causes both gastric and duodenal ulcers and is associated with gastric cancer and lymphoma. This microorganism synthesizes fucosylated oligosaccharides, predominantly the Galb-1,4GlcNAc (Type II) blood group antigens Lewis X and Y, whereas a small population also expresses the Galb-1,3GlcNAc (Type I) blood group antigens Lewis A and B. These carbohydrate structures are known to mimic host cell antigens and permit the bacteria to escape from the host immune response. Here, we report the cloning and characterization of a novel H. pylori alpha-1,4 fucosyltransferase (FucT). In contrast to the family members characterized to date, this enzyme shows exclusively Type I acceptor substrate specificity. The enzyme consisting of 432 amino acids (MW 50,502 Da) was cloned using a polymerase chain reaction (PCR)-based approach. It exhibits a high degree of identity (75-87%) and similar structural features, for example, in the heptamer repeat pattern, with other H. pylori FucTs. The kinetic characterization revealed a very efficient transferase (k(cat)/Km = 229 mM(-1) s(-1)) for the Type I acceptor substrate (Gal)-1,3 GlcNAc-Lem (1). Additionally, the enzyme possesses a broad tolerance toward nonnatural Type I acceptor substrate analogs and therefore represents a valuable tool for the chemoenzymatic synthesis of Lewis A, sialyl Lewis A as well as mimetics thereof.
Rabbani
Said
S
Institute of Molecular Pharmacy, Pharmacenter, University of Basel, Klingelbergstrasse 50, CH-4056 Basel, Switzerland.
Miksa
Viktoria
V
Wipf
Beat
B
Ernst
Beat
B
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D005033:Ethylmaleimide / Q000494:pharmacology; D005647:Fucosyltransferases / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic; D016480:Helicobacter pylori / Q000201:enzymology*; D007700:Kinetics; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012995:Solubility
D001426:Bacterial Proteins; D011994:Recombinant Proteins; D005647:Fucosyltransferases; C019818:3-galactosyl-N-acetylglucosaminide 4-alpha-L-fucosyltransferase; D005033:Ethylmaleimide