MULTICANONICAL SIMULATIONS OF SOME PEPTIDES

Tarık ÇELİK
Department of Physics Engineering, Hacettepe University,
Ankara, TURKEY

ABSTRACT

In complex systems with many degrees
of freedom such as peptides and proteins there exist a huge number of
localminimumenergy states. Conventional simulations in the canonical
ensemble get trapped in states of these energy local minima. The results
thus will depend strongly on the initial conditions Multicanonical method
overcomes this difficulty by performing a random walk in energy space and
samples much wider phase space than by conventional methods.
A brief discussion of the
multicanonical simulation method [1] will be given. The determination of
the a priori unknown multicanonical weight factors by recursion will be
shown. The intermediate steps of the simulation method starting from a
given sequence as the input leading to the folded three dimensional
structure and the minimization procedure will be shown [2]. The comparison
to the canonical simulations at fixed temperature and the effectiveness of
the multicanonical simulation method will be discussed and simulations of
some short peptides will be presented [3].

REFERENCES 
[1] B. A. Berg and T. Çelik,
Pys. Rev. Lett. 69 (1992) 2292. 
[2] F. Yaşar, T. Çelik,
B. Berg and H. Meirovitch, J. Comp. Chem. 21 (2000) 1251. 
[3] H. Arkın, F. Yaşar,
H. Köksel, S. Çelik and T. Çelik, Int. J. Mod. Phys. C 11(8) (2000)
1595; C 12(2) (2001) 281. 