Real-time dynamic single-molecule protein sequencing on an integrated semiconductor device.

Studies of the proteome would benefit greatly from methods to directly sequence and digitally quantify proteins and detect posttranslational modifications with single-molecule sensitivity. Here, we demonstrate single-molecule protein sequencing using a dynamic approach in which single peptides are probed in real time by a mixture of dye-labeled N-terminal amino acid recognizers and simultaneously cleaved by aminopeptidases. We annotate amino acids and identify the peptide sequence by measuring fluorescence intensity, lifetime, and binding kinetics on an integrated semiconductor chip. Our results demonstrate the kinetic principles that allow recognizers to identify multiple amino acids in an information-rich manner that enables discrimination of single amino acid substitutions and posttranslational modifications. With further development, we anticipate that this approach will offer a sensitive, scalable, and accessible platform for single-molecule proteomic studies and applications.

(eta5-cyclopentadienyl)(N,N-dimethyldithiocarbamato-kappa2S,S')[eta4-tetrakis(trifluoromethyl)cyclobutadienyl]molybdenum(IV).

The title complex, [Mo(C8F12)(C5H5)(C3H6NS2)], contains both a eta4-C4(CF3)4 cyclobutadienyl ligand with approximate C4v local symmetry and a eta5-C5H5 cyclopentadienyl ring. The centroids of the rings and the S atoms of a chelating dithiocarbamate ligand define the pseudo-tetrahedral coordination of the Mo atom. The Mo-C(cyclobutadienyl) bond lengths [2.189 (2)-2.211 (2) A] are unusually short, probably reflecting strong electron withdrawal by the trifluoromethyl groups. The molecules straddle crystallographic mirror planes.

Clinical implications of the innervation of the temporomandibular joint.

The successful management of temporomandibular joint (TMJ) pain remains elusive. Often, the initial relief of pain is complicated by recurrence of the symptoms. This time frame suggests that the pain may be related to neuromas of the nerves that innervate the TMJ. The current study attempted to define the innervation pattern of the TMJ as identified in 16 embalmed and 8 fresh-frozen specimens. In each specimen, the auriculotemporal nerve, a branch of the mandibular portion (V3) of the trigeminal nerve, was found to innervate the lateral capsule of the TMJ. In 75% of the specimens, the masseteric nerve, a branch of the maxillary portion (V2) of the trigeminal nerve, was found to innervate the anteromedial capsule of the TMJ. In 33% of the specimens, there was a branch coming through the mandibular notch to innervate the anteromedial capsule that was not from the masseteric nerve; this nerve is believed to have passed through the lateral pterygoid muscle after leaving V2. These consistent patterns of innervation of the TMJ suggest that diagnostic nerve blocks can be done to determine the pain pathway in these patients. It is suggested that if the nerve blocks are successful, TMJ denervation may be a future method of pain relief in patients with recalcitrant or recurrent TMJ pain.