PHOEBUS LEVENE

PHOEBUS LEVENE
BORN: February 1869
STUDIED: Imperial Military Medical Academy 

Phoebus Levene was a Russian Chemist. Some of Phoebus Levene’s greatest discoveries were within the chemical structure of molecules and components that make up DNA. Levene's research involved the hydrolysis of yeast. In the year 1905 Levene discovered the carbohydrate/sugar component of RNA (ribose sugar). Later in 1920's, he discovered deoxyribose. The two sugars differentiate between DNA and RNA.

Proposed Tetramere structure of DNA by Levene

1919- He proposed that nucleic acids were composed of a series of nucleotides. He also proposed that the chemical components of a single nucleotide contain a nitrogenous base, ribose sugar, and a phosphate group. Although this information was previously known Pauling was able to illustrate the relationship between the molecules and components. 

The Tetra nucleotide Hypothesis: Phoebus Levene proposed that the structure of DNA was a continuous tetramer as shown: 

 With this knowledge Levene concluded that the nitorogenous bases that make up nucleotides arrange theselves in a contiuous manner and that they always lined themselves accordingly. Although this statement is correct the model proposed by Linus was not. This can be deduced from the model that we know today whereby the continuous pairing of Adenine (A) with Thymine (T) and Cytosine (C) with Guanine (G). However, the model that he proposed varies with the one we identify with today. 
The structure suggests that Adenine has the ability to bond to both Thymine and Cytosine, which we know is not true. The only pairing that can occur is between the nitrogenous bases via hydrogen bonding. The tetramer model proposes that all bonds between the nucleotides take place between the phosphate groups.