The cytoplasmic domain of rat synaptotagmin I enhances synaptic transmission.

Synaptotagmin, an integral membrane protein of synaptic vesicles, functions as a calcium sensor in the temporal control of neurotransmitter release. Although synaptotagmin facilitates lipid membrane fusion in biochemical experiments, overexpression of synaptotagmin inhibits neurotransmission. A facilitatory effect of synaptotagmin on synaptic transmission was never observed.

Structural insights into immune recognition of the severe acute respiratory syndrome coronavirus S protein receptor binding domain.

The spike (S) protein of the severe acute respiratory syndrome coronavirus (SARS-CoV) is responsible for host cell attachment and fusion of the viral and host cell membranes. Within S the receptor binding domain (RBD) mediates the interaction with angiotensin-converting enzyme 2 (ACE2), the SARS-CoV host cell receptor. Both S and the RBD are highly immunogenic and both have been found to elicit neutralizing antibodies.

Crystal structure of murine CstF-77: dimeric association and implications for polyadenylation of mRNA precursors.

Cleavage stimulation factor (CstF) is a heterotrimeric protein complex essential for polyadenylation of mRNA precursors. The 77 kDa subunit, CstF-77, is known to mediate interactions with the other two subunits of CstF as well as with other components of the polyadenylation machinery. We report here the crystal structure of the HAT (half a TPR) domain of murine CstF-77, as well as its C-terminal subdomain.

The use of in situ proteolysis in the crystallization of murine CstF-77.

The cleavage-stimulation factor (CstF) is required for the cleavage of the 3'-end of messenger RNA precursors in eukaryotes. During structure determination of the 77 kDa subunit of the murine CstF complex (CstF-77), it was serendipitously discovered that a solution infected by a fungus was crucial for the crystallization of this protein. CstF-77 was partially proteolyzed during crystallization; this was very likely to have been catalyzed by a protease secreted by the fungus.

Immunogenicity of a receptor-binding domain of SARS coronavirus spike protein in mice: implications for a subunit vaccine.

We studied the immunogenicity of an anti-SARS subunit vaccine comprised of the fragment of the SARS coronavirus (SARS-CoV) spike protein amino acids 318-510 (S318-510) containing the receptor-binding domain. The S protein fragment was purified from the culture supernatant of stably transformed HEK293T cells secreting a tagged version of the protein. The vaccine was given subcutaneously to 129S6/SvEv mice in saline, with alum adjuvant or with alum plus CpG oligodeoxynucleotides (ODN).

Comparative evaluation of two severe acute respiratory syndrome (SARS) vaccine candidates in mice challenged with SARS coronavirus.

Two different severe acute respiratory syndrome (SARS) vaccine strategies were evaluated for their ability to protect against live SARS coronavirus (CoV) challenge in a murine model of infection. A whole killed (inactivated by beta-propiolactone) SARS-CoV vaccine and a combination of two adenovirus-based vectors, one expressing the nucleocapsid (N) and the other expressing the spike (S) protein (collectively designated Ad S/N), were evaluated for the induction of serum neutralizing antibodies and cellular immune responses and their ability to protect against pulmonary SARS-CoV replication. The whole killed virus (WKV) vaccine given subcutaneously to 129S6/SvEv mice was more effective than the Ad S/N vaccine administered either intranasally or intramuscularly in inhibiting SARS-CoV replication in the murine respiratory tract.

Crystal structure of the N-terminal domain of the group B streptococcus alpha C protein.

Group B Streptococcus (GBS) is the leading cause of bacterial pneumonia, sepsis, and meningitis among neonates and an important cause of morbidity among pregnant women and immunocompromised adults. Invasive diseases due to GBS are attributed to the ability of the pathogen to translocate across human epithelial surfaces. The alpha C protein (ACP) has been identified as an invasin that plays a role in internalization and translocation of GBS across epithelial cells.

Alpha C protein of group B Streptococcus binds host cell surface glycosaminoglycan and enters cells by an actin-dependent mechanism.

Group B Streptococcus (GBS) colonizes mucosal surfaces of the human gastrointestinal and gynecological tracts and causes disease in a wide range of patients. Invasive illness occurs after organisms traverse an epithelial boundary and enter deeper tissues. Previously we have reported that the alpha C protein (ACP) on the surface of GBS mediates GBS entry into ME180 cervical epithelial cells and GBS translocation across layers of these cells.