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Biomedical subjects

G Pieczenik

Publications and source records attributed to G Pieczenik.

11 recordsLinked to original sources
PubMed1994

The theory of genotypic selection: predicting the direction of evolution as a consequence of G:U base pairing and the existence of non-pathogenic strains of HIV-1.

One aspect of the Theory of Genotypic Selection states that G:U base pairs are selected for function and structure. RNA secondary structures stabilised by G:U base pairs are suggested to be involved in the evolution of attenuated strains of polio virus. Asymmetric mutations (C-->U and A-->G) and convergent evolutionary solutions are explained as a direct consequence of G:U base pairing. The possibility of a naturally occurring attenuated strain of HIV-1 is predicted.

Base Composition↗
PubMed1984

Structural and combinatorial constraints on base pairing in large nucleotide sequences.

In this paper we discuss the constraints and combinatorial problems of folding long RNA and single stranded DNA molecules into base paired structures. A computer code FOLD-A was designed to perform base pairing foldings of very long sequence chains and search for low energy configurations. The logic of the FOLD-A algorithm is described in some detail. The applications of FOLD-A to the A-protein gene of MS2 and the whole genome of the phi X 174 phage with over 5300 bases are discussed in the accompanying paper.

Base Composition↗
PubMed1984

Folding of two large nucleotide chains.

We have already described the FOLD-A code designed for folding mRNA's and single stranded DNA molecules (Nussinov & Pieczenik, 1984). In this paper we describe its application to two long polynucleotide chains: the A protein gene of the MS2 RNA and the whole genome of the phi X 174 phage. The folded form of the single stranded DNA of the phi X 174 is a six armed star with the origin of replication in its center.

Bacteriophage phi X 174↗
PubMed1980

Predicting coding function from nucleotide sequence or survival of "fitness" of tRNA.

The sequence of a nucleotide region of f1 bacteriophage was determined on a bonded ultrathin acrylamide gel with a discontinuous buffer system by using the dideoxy-DNA sequencing method. This sequence and one other were analyzed for maximal base pairing with tRNAs. The results allow a prediction of the direction and phase of possible coding functions. The implication of sequence constraints on mRNA codon frequency, tRNA structure, the origin of protein synthesis, and triplet reading are discussed in terms of neutral, Darwinian, and genotypic selectionist perspectives of evolution. The model of F. H. C. Crick, S. Brenner, A. Klug, and G. Pieczenik [(1976) Origins of Life 7, 389-397] for the origin of the genetic code is used to interpet contemporary adaptive and functional nucleic acid sequences.

Anticodon↗
PubMed1976

A speculation on the origin of protein synthesis.

It is suggested that protein sythesis may have begun without even a primitive ribosome if the primitive tRNA could take up two configuration and could bind to the messenger RNA with five base-pairs instead of the present three. This idea would impose base sequence restriction on the early messages and on the early genetic code such that the first four amino acids coded were glycine, serine, aspartic acid and aspargine. A possible mechanism is suggested for the polymerization of the early message.

Anticodon↗