Multivalent polyions can undergo complex coacervation, producing membraneless 
compartments that accumulate ribozymes and enhance catalysis, and offering a 
mechanism for functional prebiotic compartmentalization in the origins of life. 
Here, we evaluate the impact of lower, more prebiotically-relevant, polyion 
multivalency on the functional performance of coacervates as compartments. 
Positively and negatively charged homopeptides with 1-100 residues and adenosine 
mono-, di-, and triphosphate nucleotides are used as model polyions. 
Polycation/polyanion pairs are tested for coacervation, and resulting 
membraneless compartments are analyzed for salt resistance, ability to provide a 
distinct internal microenvironment (apparent local pH, RNA partitioning), and 
effect on RNA structure formation. We find that coacervates formed by phase 
separation of the shorter polyions more effectively generated distinct pH 
microenvironments, accumulated RNA, and preserved duplexes than those formed by 
longer polyions. Hence, coacervates formed by reduced multivalency polyions are 
not only viable as functional compartments for prebiotic chemistries, they can 
outperform higher molecular weight analogues.