Melittin, a 26-residue peptide from bee venom, is transformed from a largely random to a largely alpha-helical conformation at elevated pH. At 3 x 10(-5) M melittin, circular dichroism spectra show a transition with a pK near 9.6. At 8 x 10(-5) M, two approximately equal transitions occur with pKs at 7.2 and 9.6. At 6 x 10(-4) M, a single transition is seen with a pK of 6.8, followed by a more gradual increase to at least pH 11. The transitions near pH 7 presumably arise from deprotonation of the alpha-amino group. When the amino groups are acetylated or succinylated, a 60% alpha-helical conformation is adopted at neutral or low pH. The acylated melittins form more stable oligomers than does native melittin.

The mammaglobin gene has been shown to be preferentially expressed in breast tissue. Few genes match its specificity. Mammaglobin has generated much interest, and studies are ongoing to develop diagnostic tests for breast cancer based on the detection of mammaglobin. While searching the Incyte Genomics Lifeseq database for tissue-specific markers, we observed a second secretoglobin, BU101, also known as lipophilin B. We report here that mammaglobin, in breast tissue, is found as a complex with BU101. The complex was isolated from breast cancer tissue and was characterized as the biologically relevant form of mammaglobin.

In this report we describe a cDNA sequence, BS106, identified from Incyte Genomics LifeSeq^® Expressed Sequence Tag database. A multi-tissue mRNA expression array, northern blots, and RT-PCR assays demonstrate the expression of BS106 in mammary, salivary and prostate glands, but not in other tissue types. BS106 mRNA was detected in 90% of the breast tissues examined. The cDNA encodes a 90-amino acid protein characterized as a small, mucin-like protein based on amino acid composition, extensive O-linked glycosylation, and expression profile. BS106 protein was recombinantly expressed in human embryonic kidney 293 cells and the secreted product was purified from the culture media. Monoclonal antibodies were prepared and used for immunohistochemical analysis of early stage breast cancer. BS106 protein was detected in the vast majority of carcinomas (70–100%) and overexpressed in approximately 30% of the 22 specimens analyzed. BS106 protein was not detected in other solid tumor types including bladder carcinoma, colon carcinoma, endometrial carcinoma, gastric carcinoma, squamous cell lung carcinoma, adenocarcinoma of the lung, ovarian carcinoma, pancreatic and prostatic carcinoma.

SynopsisPoly(N'-trimethyl-L-lysine), [Lys(Me3)],, and poly(N6-trimethyl-L-ornithine), [Orn(Me3)],, in sodium dodecylsulfate do not assume the p-structure or a-helix, respectively, of their parent polymers. In 0.5M Ca(C104)Z both [Lys(Mea)], and [Orn(Me3)], are aggregated and display CD spectra indicative of a regular, perhaps helical, structure. We have begun a study of the interactions of nucleic acids with polypeptides containing alkylated basic residues, as models for methylated proteins. Here we present data on the conformational properties of poly-(N'-trimethyl-L-lysine), [Lys(Mes)],, and poly(N*-trimethyl-L-ornithine), [Orn(Medl,. MATERIAL A N D METHODS MaterialsPoly(L-1ysine)aHBr (molecular weight 30,000) was purchased from Sigma Chemical Co., and poly(L-ornithine).HBr (molecular weight 28,000) was purchased from Miles Laboratories. N€-Monomethyllysine was purchased from Sigma Chemical Co., and N'-dimethyllysine was purchased from Calbiochem. Sodium dodecylsulfate (NaDodSO4), 99% pure, was purchased from Pierce Chemical Co. Methods[Lys(Mes)], and [Orn(Mes)], were prepared by methylation with dimethylsulfate (DMS). For example, 1 ml DMS was added to 25 mg [LysHBr], in 10 ml H20 and 3 ml ethanol. The pH was adjusted to 9.5 and