In our continuation of the structure-based design of anti-trypanosomatid drugs, parasite-selective adenosine analogues were identified as low micromolar inhibitors of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Crystal structures of Trypanosoma brucei, Trypanosoma cruzi, Leishmania mexicana, and human GAPDH's provided details of how the adenosyl moiety of NAD + interacts with the proteins, and this facilitated the understanding of the relative affinities of a series of adenosine analogues for the various GAPDH's. From exploration of modifications of the naphthalenemethyl and benzamide substituents of a lead compound, N 6 -(1-naphthalenemethyl)-2′-deoxy-2′-(3-methoxybenzamido)adenosine (6e), N 6 -(substituted-naphthalenemethyl)-2′-deoxy-2′-(substituted-benzamido)adenosine analogues were investigated. N 6 -(1-Naphthalenemethyl)-2′-deoxy-2′-(3,5-dimethoxybenzamido)adenosine (6m), N 6 -[1-(3-hydroxy-naphthalene)methyl]-2′-deoxy-2′-(3,5-dimethoxybenzamido)adenosine (7m), N 6 -[1-(3-methoxy-naphthalene)methyl]-2′-deoxy-2′-(3,5-dimethoxybenzamido)adenosine (9m), N 6 -(2-naphthalene-methyl)-2′-deoxy-2′-(3-methoxybenzamido)adenosine (11e), and N 6 -(2-naphthalenemethyl)-2′-deoxy-2′-(3,5-dimethoxybenzamido)adenosine (11m) demonstrated a 2-to 3-fold improvement over 6e and a 7100-to 25000-fold improvement over the adenosine template. IC 50 's of these compounds were in the range 2-12 μM for T. brucei, T. cruzi, and L. mexicana GAPDH's, and these compounds did not inhibit mammalian GAPDH when tested at their solubility limit. To explore more thoroughly the structure-activity relationships of this class of compounds, a library of 240 N 6 -(substituted)-2′-deoxy-2′-(amido)adenosine analogues was generated using parallel solution-phase synthesis with N 6 and C2′ substituents chosen on the basis of computational docking scores. This resulted in the identification of 40 additional compounds that inhibit parasite GAPDH's in the low micromolar range. We also explored adenosine analogues containing 5′-amido substituents and found that 2′,5′-

This cranio-morphometric study emphasizes a “two-layer model” for eastern Eurasian anatomically modern human (AMH) populations, based on large datasets of 89 population samples including findings directly from ancient archaeological contexts. Results suggest that an initial “first layer” of AMH had related closely to ancestral Andaman, Australian, Papuan, and Jomon groups who likely entered this region via the Southeast Asian landmass, prior to 65–50 kya. A later “second layer” shared strong cranial affinities with Siberians, implying a Northeast Asian source, evidenced by 9 kya in central China and then followed by expansions of descendant groups into Southeast Asia after 4 kya. These two populations shared limited initial exchange, and the second layer grew at a faster rate and in greater numbers, linked with contexts of farming that may have supported increased population densities. Clear dichotomization between the two layers implies a temporally deep divergence of distinct migration routes for AMH through both southern and northern Eurasia.

Protein prenylation occurs in the protozoan that causes African sleeping sickness (Trypanosoma brucei), and the protein farnesyltransferase appears to be a good target for developing drugs. We have cloned the ␣-and ␤-subunits of T. brucei protein farnesyltransferase (TB-PFT) using nucleic acid probes designed from partial amino acid sequences obtained from the enzyme purified from insect stage parasites. TB-PFT is expressed in both bloodstream and insect stage parasites. Enzymatically active TB-PFT was produced by heterologous expression in Escherichia coli. Compared with mammalian protein farnesyltransferases, TB-PFT contains a number of inserts of >25 residues in both subunits that reside on the surface of the enzyme in turns linking adjacent ␣-helices. Substrate specificity studies with a series of 20 peptides SSCALX (where X indicates a naturally occurring amino acid) show that the recombinant enzyme behaves identically to the native enzyme and displays distinct specificity compared with mammalian protein farnesyltransferase. TB-PFT prefers Gln and Met at the X position but not Ser, Thr, or Cys, which are good substrates for mammalian protein farnesyltransferase. A structural homology model of the active site of TB-PFT provides a basis for understanding structureactivity relations among substrates and CAAX mimetic inhibitors.