Here are some ideas for your papers. I would prefer you to come up with your own idea, but if you get stuck, any of these ideas would be OK. Your paper should not be based on just a single reference; those cited are to get you started! Search for more.

Topic	Lead Reference	What's Cool
Aldolase-catalyzed condensations	Wong et al., Science , 2001, 294, 369	The aldolase active site can accomodate multiple substrates
Parallel b-helices in proteins	Berger et al., Proc. Natl. Acad. Sci., 2001, 98, 14819	The motif is much more common in surface proteins of disease organisms than in non-pathogenic microbes
Bacterial chaperones	Galan and Stebbins, Nature, 2001, 414, 77	Bacterial chaperones keep proteins unfolded to ease injection into cells
"Mad Neanderthal" Disease	Med. Hypotheses, 2008, 71, 4; Science, 2003, 300, 227	Did prion diseases kill off the Neanderthals?
NMR structure of an enzyme catalytic site	Kern et al., Science, 2002, 295, 1520	Movements of the enzyme backbone during catalysis are detected
Family Tree of Bears	Proc. Natnl. Acad. Sci., 2008, 105, 17447; BMC Evol. Biol., 2008, 8, 220	Analyses of the mitochondrial DNA of extinct bears
How amino acids form in space	Bernstein, Nature, 2002, 416, 401, 403	These amino acids may be older than the solar system
Where did we come from?	Sykes, The Seven Daughters of Eve, Norton, 2001	We are all descended from one woman who lived 130,000 years ago; discuss the scientific evidence
Y-chromsomal Adam?	Proc. Nat. Acad. Sci., 1996, 93, 196; Nature Genetics, 2000, 26, 388; Mol. Biol. Evol., 2001, 18, 1189	Are men necessary?
DNA Repair	Chem. Rev., 2003, 103, 2729	Is removal of damaged bases SN1 or SN2?
Designing Protein-Protein Interactions	Science, 2008, 319, 206	Making proteins hang out together
How RNA folds	Curr. Opin. Struct. Biol., 2003, 13, 309	What is the mechanistic relationship between folding and sequence?

Here are a couple of examples of good papers from a few years ago: