Cystosolic chaperonin subunits have a conserved ATPase domain but diverged polypeptide-binding domains

CCT (also called the TCP-1 complex or TriC) is a chaperonin found in the eukaryotic cytosol, and has unique structural and functional features. Unlike homo-oligomeric chaperonins, CCT comprises at least eight different subunits, and appears to have a limited range of physiological substrates. We have analysed CCT sequences in light of the recent determination of the crystal structure and mutational identification of the functional domains of the bacterial chaperonin GroEL. A high level of identity among all chaperonin subunits is observed in those regions that correspond to the ATP-binding site of GroEL. By contrast, no significant identity is shared in the region corresponding to the polypeptide-binding region of GroEL, either between CCT subunits or between CCT subunits and GroEL. This suggests that the polypeptide-binding sites of CCT subunits have diverged both from each other and from GroEL, which may explain the apparently different range of substrates recognized by CCT.     

Roaring rhythms in black howler monkeys (Alouatta pigra) of Belize

Roaring was recorded during 15-min intervals for 55 days from April 29 to July 14, 1981 in the area around Bermuda Landing, Belize. Roaring profiles were compiled to represent four three-week periods in which roaring was graphed against the time of day. Rates of roaring were also calculated for three troops. Results indicate a gradual change in the daily profile of roaring from dry to rainy season. The marked bimodality of roaring at dawn and dusk in the dry season changed to a more dampened bimodality with reduced dawn and dusk peaks and more roaring during the midday in the rainy season. This seems related to the decreased hours of sun and the amount of rain during the wet season. Additionally, literature on monkeys with long range vocalizations suggests that bimodal peaks in calling may be more prevalent in species which display territorial defense.