scholarly journals Importance of C-Terminal Knot Structure in Carbonic Anhydrase II (Part I): Role of C-Terminal Knot Forming GLN253 on Enzymatic Property of Human Carbinic II

1970 ◽  
Vol 14 ◽  
pp. 1-9
Author(s):  
Mohammad Taufiq Alam
Keyword(s):  
Amino Acid ◽  
Carbonic Anhydrase ◽  
Point Mutation ◽  
Amino Acid Residue ◽  
Active Site ◽  
Terminal Region ◽  
Carbonic Anhydrase Ii ◽  
C Terminus ◽  
Human Carbonic Anhydrase

In both, bovine and human carbonic anhydrase II, a conserved glutamine residue occupies the position in the middle of the knot, which is formed by intercrossing of C-terminal end with N-terminal region. Previous studies have indicated that C-terminus is not the part of an active site, but truncation of 7 amino acid residue in this region can have marked effects on stability of the enzyme (data not published). To gain further insight into the role of specific amino acid residue in C-terminal region, site directed mutagenesis was used to introduce point mutation. Substitution of glutamine with cysteine was chosen because the cysteine residue is less hydrophilic as compared with glutamine and thus, may disrupt the hydrophilic environment in this region. Result indicates that Gln253 located within the C-terminus knot topology plays a significant role in normal function of the enzyme. Thus, C-terminal region might mediate cooperativity between the central active site of the enzyme through proper formation of knot. Key words: Human carbonic anhydrase II; knot topology; point mutation J. bio-sci. 14: 1-9, 2006

scholarly journals Kinetic and crystallographic studies of the role of tyrosine 7 in the active site of human carbonic anhydrase II

2011 ◽  
Vol 506 (2) ◽  
pp. 181-187 ◽  
Author(s):  
Rose Mikulski ◽  
Balendu Sankara Avvaru ◽  
Chingkuang Tu ◽  
Nicolette Case ◽  
Robert McKenna ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Active Site ◽  
Carbonic Anhydrase Ii ◽  
Human Carbonic Anhydrase

scholarly journals CRISPR/Cas9-mediated mutation revealed cytoplasmic tail is dispensable for IZUMO1 function and male fertility

Reproduction ◽  
2016 ◽  
Vol 152 (6) ◽  
pp. 665-672 ◽  
Author(s):  
Samantha A M Young ◽  
Haruhiko Miyata ◽  
Yuhkoh Satouh ◽  
Masanaga Muto ◽  
Martin R Larsen ◽  
...  
Keyword(s):  
Amino Acid ◽  
Point Mutation ◽  
Male Fertility ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Cytoplasmic Tail ◽  
Binding Partner ◽  
C Terminus ◽  
Manipulation System

IZUMO1 is a protein found in the head of spermatozoa that has been identified as essential for sperm–egg fusion. Its binding partner in the egg has been discovered (JUNO); however, the roles of several domains within IZUMO1 remain unexplored. One such domain is the C-terminus, which undergoes major phosphorylation changes in the cytoplasmic portion of the protein during rat epididymal transit. However, the cytoplasmic tail of IZUMO1 in many species is highly variable, ranging from 55 to one amino acid. Therefore, to understand the role of the cytoplasmic tail of IZUMO1 in mouse, we utilised the gene manipulation system of CRISPR/Cas9 to generate a point mutation resulting in a premature stop codon, producing mice with truncated IZUMO1. Mice without the cytoplasmic tail of IZUMO1 showed normal fertility but decreased the amount of protein, indicating that whilst this region is important for the expression level of IZUMO1, it is dispensable for fertilisation in the mouse.

Abstract 52: The Role of Kindlin-2 in Integrin Activation Depends on a Short C-Terminal Region

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Jamila Hirbawi ◽  
Kamila Bledzka ◽  
Yan Qing Ma ◽  
Jun Qin ◽  
Edward F Plow
Keyword(s):  
Amino Acids ◽  
Point Mutation ◽  
Single Point ◽  
Terminal Region ◽  
Membrane Receptors ◽  
Single Point Mutation ◽  
Loss Of Function ◽  
Integrin Activation ◽  
C Terminus

Integrins are heterodimeric cell membrane receptors that regulate cell adhesion, migration, and survival. The kindlins are known to be key regulators of integrin activation, the transition from a low affinity, default state to a high affinity state for ligand. This function depends on their binding, together with talin, to the cytoplasmic tails (CT) of the β subunit of integrins. Kindlins are FERM domain containing proteins, and it is its F3 (PTB) subdomain of the FERM that is the primary binding site for integrin β CT. At its very C-terminus, beyond the F3, is a short extension of 21 amino acids, K2 660-680, and we have focused on the role of this region in the co-activator function of kindlin-2 (K2). For this analysis, we performed PAC-1 (antibody to detect activated αIIbβ3 integrin) binding assays in CHO cells stably expressing integrin α IIb β 3 that were transiently transfected with talin head domain and K2 mutants. Expression levels of all proteins were verified to be similar by western blotting and FACS. Truncation of K2 at residue 660 essentially eliminated the co-activator function of K2. Deletion of smaller segments also reduced co-activator activity by 50% to 100%. Deletion of just the last two amino acids in the sequence, W 679 V 680 , resulted in a 50% reduction in co-activator activity and a single point mutation of Y 673 A also led to a 50% loss of function. A combination mutant consisting of the W 679 V 680 deletion and the Y 673 point mutation resulted in 100% loss of kindlin-2 co-activator activity. Pull-down experiments performed using GST tagged β 3 CT and CHO lysates transfected with GFP-kindlin-2 forms suggested that the C-terminal deletion did not disrupt binding to β 3 CT. This observation was corroborated by surface plasmon resonance studies in which the binding of full-length K2 and K2Δ666C (Δ666) was compared, and their K D values for immobilized β3 CT were found to be essentially the same. Overall, these data establish an important and unanticipated role of the carboxy-terminal region of kindlin-2 in its integrin co-activator function that is not dependent of its binding to integrin.

Role of histidine 64 in the catalytic mechanism of human carbonic anhydrase II studied with a site-specific mutant

Biochemistry ◽  
1989 ◽  
Vol 28 (19) ◽  
pp. 7913-7918 ◽  
Author(s):  
Chingkuang Tu ◽  
David N. Silverman ◽  
Cecilia Forsman ◽  
Bengt Harald Jonsson ◽  
Sven Lindskog
Keyword(s):  
Carbonic Anhydrase ◽  
Catalytic Mechanism ◽  
Carbonic Anhydrase Ii ◽  
Site Specific ◽  
Human Carbonic Anhydrase ◽  
A Site

Out of the active site binding pocket for carbonic anhydrase inhibitors

2015 ◽  
Vol 51 (2) ◽  
pp. 302-305 ◽  
Author(s):  
Katia D'Ambrosio ◽  
Simone Carradori ◽  
Simona M. Monti ◽  
Martina Buonanno ◽  
Daniela Secci ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Active Site ◽  
Binding Pocket ◽  
Carbonic Anhydrase Ii ◽  
Carbonic Anhydrase Inhibitors ◽  
Human Carbonic Anhydrase ◽  
Site Binding

2-Benzylsulfinylbenzoic acid binds to human carbonic anhydrase II in a mode completely different from any other class of carbonic anhydrase inhibitors investigated so far.

scholarly journals Effect of Active-site Mutation at Asn67 on the Proton Transfer Mechanism of Human Carbonic Anhydrase II

Biochemistry ◽  
2009 ◽  
Vol 48 (33) ◽  
pp. 7996-8005 ◽  
Author(s):  
C. Mark Maupin ◽  
Jiayin Zheng ◽  
Chingkuang Tu ◽  
Robert McKenna ◽  
David N. Silverman ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Proton Transfer ◽  
Active Site ◽  
Transfer Mechanism ◽  
Carbonic Anhydrase Ii ◽  
Site Mutation ◽  
Human Carbonic Anhydrase
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