Areas EPG, Pasccutti PG, Schreier S, Mundim KC, Bisch PM
BRAZILIAN JOURNAL OF MEDICAL AND BIOLOGICAL RESEARCH
27: (2) 527-533 FEB 1994
Cited References : 7
Times Cited : 5
Abstract:
We used a recently developed
software that mimics a cytoplasm/membrane environment, with an interface
separating two continuous media of different dielectric constants (1).
This software has been designed to allow modelling of different kinds of
molecules of biological interest such as proteins and drugs, in each of
the isolated continuous media, as well as in their interactions with membrane-like
structures,making use of the dielectric discontinuity represented by the
interface. In the present study we have applied this program (''THOR'')
to model a polypeptide sequence corresponding to a 50% active mutant of
the signal sequence of the lamB gene product of E. coli, known as maltoporin
or lambda receptor (2). The peptide was first submitted to optimization
of its molecular geometry followed by molecular dynamics in water (epsilon
= 80) until thermalization was achieved. The conformation evolved from
a rather extended random conformation to increasingly folded structures.
The presence of the dielectric discontinuity induced the movement of the
molecule's center of mass from water towards the interface. The entry of
the peptide into the lower dielectric constant medium (epsilon = 2) through
the interface was paralleled by a decrease in the total potential energy,
indicating the affinity of the peptide for the lipid-mimetic phase.
Author Keywords:
MOLECULAR DYNAMICS, SIGNAL PEPTIDES, PROTEIN CONFORMATION, MEMBRANES
KeyWords Plus: STABILITY
Addresses:
UNIV SAO PAULO, INST QUIM, DEPT BIOQUIM, BR-01498970 SAO PAULO, BRAZIL.
UNIV SAO PAULO, INST FIS, SAO PAULO, BRAZIL.
UNIV FED BAHIA, INST FIS, BR-40110060 SALVADOR, BA, BRAZIL.
CTR BRASILEIRO PESQUISAS FIS, CNPQ, BR-22290000 RIO JANEIRO, BRAZIL.
Publisher: ASSOC BRAS DIVULG CIENTIFICA, SAO PAULO
IDS Number: MX609
ISSN: 0100-879X