Exploring the 3D structure of the N-acetylglucosaminyltransferase V (GnT-V).

 

Stanislav Kozmon1,2, Igor Tvaroška2

 

1NCBR, University campus, Kamenice 5, 625 00 Brno, Czech Republic

2Institute of Chemistry, Slovak Academy of Sciences, 845 38 Bratislava, Slovakia

stano@chemi.muni.cz

 

 

Glycosyltransferases (GT’s) are indispensable to cellular life in eukaryotes by producing glycan linkages with a unique contribution to the development and function of physiological systems in the context of living organisms. Also connections between GT’s and mammalian disease processes are being made recently. In this group of glycosyltransferases is β-1,6-N-acetylglucosaminyltransferase V (GnT-V) also included. Genetic experiments on mice with blocked GnT-V production (Mgat5-/- knockout) clearly show reduction in cancer metastasis [1]. Due to the clear evidence of the involvement GnT-V in the cancer metastasis is only little information on the structure and reaction mechanism.

In the present study, we have attempted to build model of the GnT-V 3D-structure. Unfortunately, it is not clear to which GT family GnT-V belongs, therefore, we used one structure from the GT-A family and one structure from the GT-B one as structure templates. Selected structures had the best primary sequence alignment with GnT-V minimal catalytic domain [2]. We have chosen structure of Core2 transferase (2GAM) [3] as the representative of the GT-A family and MurG transferase (1NLM) [4] as the representative of the GT-B family, respectively. We made several alignments employing different algorithms, namely with Blosum62, 120PAM or 3D-PSSM. We obtain altogether 10 models of the GnT-V structure. On the basis of the 3D-structure analysis we have chosen five models for the molecular dynamic equilibration in water. All structure models have been equilibrated at 300 K during 4ns. The molecular dynamic simulation show, that more reliable model might be the model based on the MurG template. Due to these result we did multiple sequence alignment with another seven members of this family, including MurG, to observe more precise alignment. In addition we also took one glycosyltransferase, which family hasn’t been specified yet, α-1,6-fucosyltransferase FUT8 (2DE0) [5].

 

References

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2.     B. Korczak, T. Le, S. Elowe, A. Datti, W.J. Dennis, Glycobiology, 10, (2003), 595.

3.     J.E. Pak, P. Arnoux, S. Zhou, P. Sivarajah, M. Satkunarajah, X. Xing,  J.M. Rini, J. Biol. Mol., 281, (2006), 26693.

4.     Y. Hu, L. Chen, S. Ha, B. Gross, B. Falcone, D. Walker, M. Mokhtarzadeh, S. Walker, Proc. Natl. Acad. Sci. USA, 100, (2003), 845.

5.     H. Ihara, Y. Ikeda, S. Toma, X. Wang, T. Suzuki, J. Gu, E. Miyoshi, T. Tsukihara, K. Honke, A. Matsumoto, A. Nakagawa, N. Taniguchi, Glycobiology, 17, (2007), 455.

 

 

Acknowledgements

 

This work was supported by the grants from ESF number JPD 3BA 2005/1-031 and from the Science and Technology Assistance Agency under contract APVV-0607-07.