ProBiS-database: precalculated binding site similarities and local pairwise alignments of PDB structures

ProBiS-Database is a searchable repository of precalculated local structural alignments in proteins detected by the ProBiS algorithm in the Protein Data Bank. Identification of functionally important binding regions of the protein is facilitated by structural similarity scores mapped to the query protein structure. PDB structures that have been aligned with a query protein may be rapidly retrieved from the ProBiS-Database, which is thus able to generate hypotheses concerning the roles of uncharacterized proteins. Presented with uncharacterized protein structure, ProBiS-Database can discern relationships between such a query protein and other better known proteins in the PDB. Fast access and a user-friendly graphical interface promote easy exploration of this database of over 420 million local structural alignments. The ProBiS-Database is updated weekly and is freely available online at http://probis.cmm.ki.si/database.     

Path and path deviation equations for <Emphasis Type="Italic">p</Emphasis>-branes

Path and path deviation equations for neutral, charged, spinning and spinning charged test particles, using a modified Bazanski Lagrangian, are derived. We extend this approach to strings and branes. We show how the Bazanski Lagrangian for charged point particles and charged branes arises à la Kaluza-Klein from the Bazanski Lagrangian in 5-dimensions.     

Derivations of noncommutative Banach algebras II

Supported in part by a grant from the Ministry of Science of Slovenia.     

Influence of the side chain protecting group on the stereoselectivity of the 1,3-dipolar cycloaddition of d-talo-configured nitrones

Two new five-membered cyclic d-talo-configured nitrones were synthesized from d-mannose, and examined in 1,3-dipolar cycloadditions with vinyl acetate and vinylene carbonate. The stereoselectivity of the cycloadditions depends greatly on the protecting group of the vicinal diol attached to the nitrone C-5 carbon atom. Methyl protection resulted in limited syn/anti-selectivity, giving mixtures of the two isomeric exo-syn and exo-anti isoxazolidines in comparable amounts. On the other hand, the cyclohexylidene-substituted nitrone reacted more selectively in favour of the syn isomer. The difference in the diastereoselectivity was attributed to the specific spatial orientation of the nitrone C-5 substituent.     

On some additive mappings in rings with involution

Summary LetR be a *-ring. We study an additive mappingD: R R satisfyingD(x ²) =D(x)x ^* +xD(x) for allx R.It is shown that, in caseR contains the unit element, the element 1/2, and an invertible skew-hermitian element which lies in the center ofR, then there exists ana R such thatD(x) = ax ^* – xa for allx R. IfR is a noncommutative prime real algebra, thenD is linear. In our main result we prove that a noncommutative prime ring of characteristic different from 2 is normal (i.e.xx ^* =x ^* x for allx R) if and only if there exists a nonzero additive mappingD: R R satisfyingD(x ²) =D(x)x ^* +xD(x) and [D(x), x] = 0 for allx R. This result is in the spirit of the well-known theorem of E. Posner, which states that the existence of a nonzero derivationD on a prime ringR, such that [D(x), x] lies in the center ofR for allx R, forcesR to be commutative.