pneumoniae, and those fromM

pneumoniae, and those fromM. consistent with the results from trypsin treatment of the cell surface. Sequence analysis of P1 adhesin and its orthologs showed that domain name I is usually well conserved and that a transmembrane segment exists near the link between domains II and III. Mycoplasmas are commensal, and occasionally parasitic, bacteria that lack a peptidoglycan layer and have small genomes (47).Mycoplasma pneumoniae, a cause of human going for walks pneumonia, forms a membrane protrusion at 1 pole and exhibits gliding motility in the direction of the protrusion (22,32-35,56). The maximum speed reaches 1 m, one-half its cell length, per second (40,51). This motility, combined with the ability to adhere to epithelial cells (20), is usually involved in the pathogenic process, enabling the cells to translocate from your suggestions of bronchial cilia to the host cell surface (24). Previous studies, including genome analyses, have shown that this motility is not related to other known mechanisms of bacterial movement, nor will it involve motor proteins known to be involved in eukaryotic cell motility (11,17,32,39,42). The gliding machinery is located at a membrane protrusion called the attachment organelle, which is composed of an internal rod-shaped cytoskeleton and nap-like surface protrusions (18,20,22,32-35). P1 adhesin, a 170-kDa protein found in mycoplasmas, binds to solid surfaces, such as host cells or glass (12,51). In the genome ofM. pneumoniae, P1 adhesin (MPN141) is usually encoded in the same operon with two other open reading frames (ORFs), MPN140 and HS-1371 MPN142 (25). The translation product of MPN142 is usually divided into two proteins by a putative endopeptidase activity (5), P40 (protein C; 45 kDa) and P90 (protein B; 83 kDa), both of which have been suggested to interact actually with P1 adhesin (26,27,52,53). MPN140 encodes a putative phosphodiesterase whose role in cytadherence is not known. It has been suggested that P1 adhesin functions as a lower leg for gliding motility, repeatedly catching and releasing surface structure, because the monoclonal antibodies against the protein reduce gliding velocity and the ability to bind to solid surfaces (51). P1 adhesin is also known as the immunodominant protein and exhibits sequence polymorphism among its clinical strains (19,57-59,65). Knowing F3 the structure and activity of P1 adhesin should be helpful in understanding the motility and antigenic variance ofM. pneumoniae. In the HS-1371 present study, we isolated native P1 adhesin fromM. pneumoniaecells and analyzed its structure. == MATERIALS AND METHODS == == Isolation HS-1371 of the P1-P90 complex. == M. pneumoniaestrain M129 (the type strain of group I) (29), whose genome has been sequenced (6,10), was produced at 37C in Aluotto medium (2,38). The following procedures were carried out at 4C unless normally noted. Cells from 1 liter of culture in the exponential phase were centrifuged at HS-1371 14,000 gfor 10 min and washed twice with phosphate-buffered saline (PBS) consisting of 75 mM sodium phosphate (pH 7.3) and 68 mM NaCl. The cells were suspended to an optical density at 600 nm of 20 in PBS made up of 0.1 mM phenylmethylsulfonyl fluoride (PMSF), 5 mM -mercaptoethanol, and 1 mM EDTA and then were mixed with CHAPS 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate to 1% (vol/vol). After gentle shaking for 5 min, the suspension was centrifuged at 25,000 gfor 20 min. The pellet was dissolved in HS-1371 one-fifth of its initial volume of PBS and then mixed withN-octyl–d-glucoside (octylglucoside) to 2% (vol/vol). After gentle shaking for 10 min at room heat (RT), the suspension was centrifuged at 25,000 gfor 20 min at RT, as explained previously (15). The supernatant was fractionated by salting out with ammonium sulfate at 45 to 55% saturation, and the insoluble portion was recovered by centrifugation at 22,000 gfor 15 min. The pellet was dissolved and then dialyzed overnight against PBS-NT made up of 75 mM sodium phosphate (pH 7.3), 400 mM NaCl, and 0.3%.