Intermolecular disulfide bonds stabilize VirB7 homodimers and VirB7/VirB9 heterodimers during biogenesis of the Agrobacterium tumefaciens T-complex transport apparatus.

The Agrobacterium tumefaciens VirB7 lipoprotein contributes to the stabilization of VirB proteins during biogenesis of the putative T-complex transport apparatus. Here, we report that stabilization of VirB7 itself is correlated with its ability to form disulfide cross-linked homodimers via a reactive Cys-24 residue. Three types of beta-mercaptoethanol-dissociable complexes were visualized with VirB7 and/or a VirB7::PhoA41 fusion protein: (i) a 9-kDa complex corresponding in size to a VirB7 homodimer, (ii) a 54-kDa complex corresponding in size to a VirB7/VirB7::PhoA41 mixed dimer, and (iii) a 102-kDa complex corresponding to a VirB7::PhoA41 homodimer. A VirB7C24S mutant protein was immunologically undetectable, whereas the corresponding VirB7C24S::PhoA41 derivative accumulated to detectable levels but failed to form dissociable homodimers or mixed dimers with wild-type VirB7. We further report that VirB7-dependent stabilization of VirB9 is correlated with the ability of these two proteins to dimerize via formation of a disulfide bridge between reactive Cys-24 and Cys-262 residues, respectively. Two types of dissociable complexes were visualized: (i) a 36-kDa complex corresponding in size to a VirB7/VirB9 heterodimer and (ii) an 84-kDa complex corresponding in size to a VirB7/VirB9::PhoA293 heterodimer. A VirB9C262S mutant protein was immunologically undetectable, whereas the corresponding VirB9C262S::PhoA293 derivative accumulated to detectable levels but failed to form dissociable heterodimers with wild-type VirB7. Taken together, these results support a model in which the formation of disulfide cross-linked VirB7 dimers represent critical early steps in the biogenesis of the T-complex transport apparatus.

The Philadelphia Transportation Company case re: income interest on bonds.

"The two volumes ... consist of a brief factual résumé of the court case with no editorial comment, followed by the record of the case in the lower court as submitted to the Supreme Court of Pennsylvania on appeal, the principal briefs, and the order of the Supreme Court."

General mortgage : Lehigh and New England Railroad Company to guarantee trust and safe deposit company, trustee : $15,000,000 general mortgage gold bonds : dated July 1, 1914, principal due July 1, 1954.

Cover-title.

Bonds and the bond market /

Includes index.

United States government bonds of the second liberty loan, what they are and how to buy them.

Mode of access: Internet.

Defaults of original issue high-yield convertible bonds /

"August 1992."

The policy of extending government aid to additional railroads to the Pacific by guaranteeing interest on their bonds : report of the majority of the Senate Committee on Pacific Railroad, February 19, 1869.

Cover title.

Marriage bonds and ministers' returns of Halifax County, Virginia, 1753-1800.

Mode of access: Internet.

Coupon bonds, and other stories.

Copyright notice on verso of t.p. dated 1871.