Understanding Ribosomal Structural Differences Between Bacteria and
Archaea Using Network Graphs
Abstract
The ribosome is a universal molecular machine (comprised of RNA and
proteins) which translates the message from the genome into proteins
(polymers of amino acids) in biology. Similar to how Flight and Cockpit
voice recorders record and preserve an aircraft’s flight history, the
ribosome has recorded signatures of its evolution. Tapping this resource
is important for understanding the origins of life. The electrostatic
properties/net positive charge(s) of ribosomal proteins (RPs) stabilize
interactions with the negatively charged ribosomal RNA (rRNA) and
influence the assembly and folding of ribosomes. A high percentage of
RPs from extremely halophilic archaea are known to be acidic/negatively
charged. Recently the net charges (at pH 7.4) of the RPs from a highly
conserved cluster of RPs were found to have an inverse relationship with
the halophilicity/halotolerance (ability to survive under salt
conditions) levels in bacteria and archaea. In non-halophilic bacteria,
these RPs are generally basic, contrasting with the acidic proteomes of
the extreme halophiles. We explore the use of a new mathematical
modeling technique based on interaction graphs to provide a systematic
understanding of the structural differences in the Large Subunit (LSU)
of the bacterium Escherichia coli and that of the extremely halophilic
archaeon Haloarcula marismortui.