Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0393754 (HSA)
 2,996 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

According to the heterogeneity of the immunogen of GA3-3-O-HSA, which contained other components such as GA3-7-CONH-HSA, two kinds of monoclonal antibodies (MAbs) against different antigen determinants of GA3 were prepared in a single process using a two-step screening assay for hybridomas. The results from a cross-reactivity experiment showed that MAb BG2 was specific for GA7/4 methyl esters (GA7/4me) with high affinity. Its affinity for GA7me was over 100 and 200 times higher than for GA3me and GA1me, respectively. Methylation of the 7-oic acid significantly increased the binding of MAb BG2 with GAs. On the contrary, the absence of a double bond or 3beta-OH in ring A and the breakdown of 19,10-gamma-lactone as well as the presence of 13-OH in ring D greatly reduced the binding of MAb BG2 with GAs. This antibody with high specificity can be used effectively to quantify and localize the main active GA7 and GA4 from the early non-hydroxylation pathway of GAs metabolism. Using this antibody, enzyme immunoassays with high sensitivity were developed which displayed linear ranges from 1.0 x 10(-14) to 1.0 x 10(-12) mol for GA4me and from 2.0 x 10(-15) to 2.0 x 10(-13) mol for GA7me.
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PMID:Preparation of monoclonal antibodies specific for methyl esters of gibberellins A7 and A4. 873 99

Protein G-related albumin-binding (GA) modules are frequently expressed on the surfaces of bacterial cells. The limited amino acid sequence variation among GA modules results in structural and functional differences with possible implications for bacterial pathogenesis and host specificity. In particular, the streptococcal G148-GA3 and F. magna ALB8-GA albumin-binding domains exhibit a degree of structural and dynamic diversity that may account for their varied affinities for different species of albumin. To explore the impact of GA module polymorphisms on albumin binding and specificity, we recently used offset recombinant PCR to shuffle seven artificially constructed representatives of the GA sequence space and scan the phage-displayed recombinant domains for mutations that supported binding to the phylogenetically distinct human and guinea pig serum albumins (HSA and GPSA) (Rozak et al. (2006) Biochemistry 45, 3263-3271). Surprisingly, phage selection revealed an overwhelming preference for a single recombinant domain (PSD-1, phage-selected domain-1) regardless of whether the phages were enriched for their abilities to bind one or both of these albumins. We describe here the NMR-derived structure, dynamics, and stability of unbound PSD-1. Our results demonstrate that increased flexibility is not a requirement for broadened specificity, as had been suggested earlier (Johansson et al. (2002) J. Mol. Biol. 316, 1083-1099), because PSD-1 binds the phylogenetically diverse HSA and GPSA even more tightly than G148-GA3 but is less flexible. The structural basis for albumin-binding specificity is analyzed in light of these new results.
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PMID:Structure, dynamics, and stability variation in bacterial albumin binding modules: implications for species specificity. 1690 68