Biomedical subjects

Kechun Zhang

Publications and source records attributed to Kechun Zhang.

4 recordsLinked to original sources

PubMed2006

Association of Fcgamma receptor IIB gene polymorphism with genetic susceptibility to systemic lupus erythematosus in Chinese populations--a family-based association study.

BACKGROUND: The aim of this study was to investigate the role of FcgammaRIIB gene in susceptibility to systemic lupus erythematosus (SLE) using family-based association analysis method, and to examine possible haplotypes between two single-nucleotide polymorphisms. OBJECTIVE: A total of 119 patients with SLE from 95 nuclear families, aged from 14 to 78 years, was selected according to 1997 criteria of American College of Rheumatology (ACR), In addition, 316 family members of these patients were also genotyped. METHODS: A family-based association study was used to explore the relationship between gene polymorphism and SLE. We studied two single-nucleotide polymorphisms (SNPs) encoding non-synonymous substitution in the FcgammaRIIB gene with respect to genetic susceptibility to SLE. The FcgammaRIIB gene was genotyped by restriction fragment length polymorphism (RFLP) method. RESULTS: Among 119 SLE patients, the frequencies of FcgammaRIIB-C50T CC, CT and TT genotypes were 12.7%, 60.7% and 26.6%, respectively. The frequencies of FcgammaRIIB-T225C TT, TC and CC genotypes were 8.1%, 61.3% and 30.6%, respectively. Four haplotypes, 50T-225C (34.1%), 50C-225C (27.7%), 50T-225T (19.7%) and 50C-50T (18.5%) were reconstructed. Univariate (single-marker) family-based association tests (FBATs) demonstrated that variant alleles at two SNPs, rs10917661 and rs1050501, in exons 2 and 5 of FcgammaRIIB gene were significantly associated with genetic susceptibility to SLE in additive model (exon 2, Z=3.444, P=0.00057; exon 5, Z=3.707, P=0.00020), respectively. Transmission/disequilibrium test (TDT) and sibship disequilibuium test (SDT) analysis showed an excess of the alleles of T (C50T) and C (T225/C) from heterozygous parents to affected offspring (chi(2)=10.88, P=0.0013; chi(2)=7.14, P=0.0105, respectively). Furthermore, the haplotype-specific FBATs showed 50T-225C (34.1%) haplotype was more frequently transmitted in SLE than other haplotypes (Z=3.539, P=0.00042). CONCLUSIONS: Our findings provide strong evidence suggesting the FcgammaRIIB-50T-225C haplotype might be the susceptible factor of SLE in Chinese population.

Adolescent↗

PubMed2006

Engineering cooperativity in biomotor-protein assemblies.

A biosynthetic approach was developed to control and probe cooperativity in multiunit biomotor assemblies by linking molecular motors to artificial protein scaffolds. This approach provides precise control over spatial and elastic coupling between motors. Cooperative interactions between monomeric kinesin-1 motors attached to protein scaffolds enhance hydrolysis activity and microtubule gliding velocity. However, these interactions are not influenced by changes in the elastic properties of the scaffold, distinguishing multimotor transport from that powered by unorganized monomeric motors. These results highlight the role of supramolecular architecture in determining mechanisms of collective transport.

Adenosine Triphosphatases↗

PubMed2006

Tuning the erosion rate of artificial protein hydrogels through control of network topology.

Erosion behaviour governs the use of physical hydrogels in biomedical applications ranging from controlled release to cell encapsulation. Genetically engineered protein hydrogels offer unique means of controlling the erosion rate by engineering their amino acid sequences and network topology. Here, we show that the erosion rate of such materials can be tuned by harnessing selective molecular recognition, discrete aggregation number and orientational discrimination of coiled-coil protein domains. Hydrogels formed from a triblock artificial protein bearing dissimilar helical coiled-coil end domains (P and A) erode more than one hundredfold slower than hydrogels formed from those bearing the same end domains (either P or A). The reduced erosion rate is a consequence of the fact that looped chains are suppressed because P and A tend not to associate with each other. Thus, the erosion rate can be tuned over several orders of magnitude in artificial protein hydrogels, opening the door to diverse biomedical applications.

Amino Acid Sequence↗

PubMed2005

Artificial polypeptide scaffold for protein immobilization.

An artificial polypeptide scaffold composed of surface anchor and protein capture domains was designed and expressed in vivo. By using a mutant E. coli phenylalanyl-tRNA synthetase, the photoreactive amino acid para-azidophenylalanine was incorporated into the surface anchor domain. Octyltrichlorosilane-treated surfaces were functionalized with this polypeptide by spin coating and photocrosslinking. The resulting protein films were shown to immobilize recombinant proteins through association of coiled coil heterodimer.

Amino Acid Sequence↗